diff --git a/includes/abstracts/abstract-wc-data.php b/includes/abstracts/abstract-wc-data.php
index c6e3ac21855..1b0627171c3 100644
--- a/includes/abstracts/abstract-wc-data.php
+++ b/includes/abstracts/abstract-wc-data.php
@@ -380,36 +380,31 @@ abstract class WC_Data {
 	/**
 	 * Set internal data prop to specified value.
 	 * @param int ...$param Prop keys followed by value to set.
-	 * @return bool
+	 * @throws WC_Data_Exception
 	 */
 	protected function set_prop() {
-		$args = func_get_args();
-
-		if ( sizeof( $args ) < 2 ) {
-			return false;
+		if ( func_num_args() < 2 ) {
+			$this->throw_exception( 'invalid_value', 'set_prop requires at least 2 parameters' );
 		}
 
-		$value  = array_pop( $args );
-		$target = &$this->_data;
+		$args  = func_get_args();
+		$value = array_pop( $args );
+		$prop  = &$this->_data;
 
 		foreach ( $args as $arg ) {
-			if ( ! isset( $target[ $arg ] ) ) {
-				return false;
-			}
-			$target = &$target[ $arg ];
+			$prop = &$prop[ $arg ];
 		}
 
-		$target = $value;
-		return true;
+		$prop = $value;
 	}
 
 	/**
 	 * Returns an invalid data WP_Error object.
 	 * @param string $message Error Message.
 	 * @param mixed $data Data the user tried to set.
-	 * @return WP_Error
+	 * @throws WC_Data_Exception
 	 */
-	protected function error( $message = '', $data = '' ) {
-		return new WP_Error( 'invalid-data', $message, $data );
+	protected function throw_exception( $error_code, $error_message, $http_status_code = 400 ) {
+		throw new WC_Data_Exception( $error_code, $error_message, $http_status_code );
 	}
 }
diff --git a/includes/abstracts/abstract-wc-order.php b/includes/abstracts/abstract-wc-order.php
index cb0a87dcba1..84c8eea8768 100644
--- a/includes/abstracts/abstract-wc-order.php
+++ b/includes/abstracts/abstract-wc-order.php
@@ -583,23 +583,23 @@ abstract class WC_Abstract_Order extends WC_Abstract_Legacy_Order {
 	 * Set order ID.
 	 * @since 2.7.0
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_id( $value ) {
-		return $this->set_prop( 'id', absint( $value ) );
+		$this->set_prop( 'id', absint( $value ) );
 	}
 
 	/**
 	 * Set parent order ID.
 	 * @since 2.7.0
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_parent_id( $value ) {
 		if ( $value && ! get_post( $value ) ) {
-			return $this->error( 'Invalid parent ID', $value );
+			$this->throw_exception( 'order_invalid_parent_id', __( 'Invalid parent ID', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'parent_id', absint( $value ) );
+		$this->set_prop( 'parent_id', absint( $value ) );
 	}
 
 	/**
@@ -633,121 +633,119 @@ abstract class WC_Abstract_Order extends WC_Abstract_Legacy_Order {
 	/**
 	 * Set order_version
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_version( $value ) {
-		return $this->set_prop( 'version', $value );
+		$this->set_prop( 'version', $value );
 	}
 
 	/**
 	 * Set order_currency
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_currency( $value ) {
 		if ( $value && ! in_array( $value, array_keys( get_woocommerce_currencies() ) ) ) {
-			return $this->error( 'Invalid currency code', $value );
+			$this->throw_exception( 'order_invalid_currency', __( 'Invalid currency code', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'currency', $value );
+		$this->set_prop( 'currency', $value );
 	}
 
 	/**
 	 * Set prices_include_tax
 	 * @param bool $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_prices_include_tax( $value ) {
-		return $this->set_prop( 'prices_include_tax', (bool) $value );
+		$this->set_prop( 'prices_include_tax', (bool) $value );
 	}
 
 	/**
 	 * Set date_created
 	 * @param string $timestamp Timestamp
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_date_created( $timestamp ) {
-		return $this->set_prop( 'date_created', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
+		$this->set_prop( 'date_created', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
 	}
 
 	/**
 	 * Set date_modified
 	 * @param string $timestamp
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_date_modified( $timestamp ) {
-		return $this->set_prop( 'date_modified', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
+		$this->set_prop( 'date_modified', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
 	}
 
 	/**
 	 * Set discount_total
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_discount_total( $value ) {
-		return $this->set_prop( 'discount_total', wc_format_decimal( $value ) );
+		$this->set_prop( 'discount_total', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set discount_tax
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_discount_tax( $value ) {
-		return $this->set_prop( 'discount_tax', wc_format_decimal( $value ) );
+		$this->set_prop( 'discount_tax', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set shipping_total
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_total( $value ) {
-		return $this->set_prop( 'shipping_total', wc_format_decimal( $value ) );
+		$this->set_prop( 'shipping_total', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set shipping_tax
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_tax( $value ) {
 		$this->set_prop( 'shipping_tax', wc_format_decimal( $value ) );
 		$this->set_total_tax( $this->get_cart_tax() + $this->get_shipping_tax() );
-		return true;
 	}
 
 	/**
 	 * Set cart tax
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_cart_tax( $value ) {
 		$this->set_prop( 'cart_tax', wc_format_decimal( $value ) );
 		$this->set_total_tax( $this->get_cart_tax() + $this->get_shipping_tax() );
-		return true;
 	}
 
 	/**
 	 * Sets order tax (sum of cart and shipping tax). Used internaly only.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	protected function set_total_tax( $value ) {
-		return $this->set_prop( 'total_tax', wc_format_decimal( $value ) );
+		$this->set_prop( 'total_tax', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set total
 	 * @param string $value
 	 * @param string $deprecated Function used to set different totals based on this.
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_total( $value, $deprecated = '' ) {
 		if ( $deprecated ) {
 			_deprecated_argument( 'total_type', '2.7', 'Use dedicated total setter methods instead.' );
 			return $this->legacy_set_total( $value, $deprecated );
 		}
-		return $this->set_prop( 'total', wc_format_decimal( $value, wc_get_price_decimals() ) );
+		$this->set_prop( 'total', wc_format_decimal( $value, wc_get_price_decimals() ) );
 	}
 
 	/*
diff --git a/includes/class-wc-order-item-coupon.php b/includes/class-wc-order-item-coupon.php
index b8f029ea5b5..9b800c6f915 100644
--- a/includes/class-wc-order-item-coupon.php
+++ b/includes/class-wc-order-item-coupon.php
@@ -110,7 +110,7 @@ class WC_Order_Item_Coupon extends WC_Order_Item {
 	/**
 	 * Set order item name.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_name( $value ) {
 		return $this->set_code( $value );
@@ -119,28 +119,28 @@ class WC_Order_Item_Coupon extends WC_Order_Item {
 	/**
 	 * Set code.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_code( $value ) {
-		return $this->set_prop( 'code', wc_clean( $value ) );
+		$this->set_prop( 'code', wc_clean( $value ) );
 	}
 
 	/**
 	 * Set discount amount.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_discount( $value ) {
-		return $this->set_prop( 'discount', wc_format_decimal( $value ) );
+		$this->set_prop( 'discount', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set discounted tax amount.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_discount_tax( $value ) {
-		return $this->set_prop( 'discount_tax', wc_format_decimal( $value ) );
+		$this->set_prop( 'discount_tax', wc_format_decimal( $value ) );
 	}
 
 	/*
diff --git a/includes/class-wc-order-item-fee.php b/includes/class-wc-order-item-fee.php
index 408ca05dca1..3cf657c90c7 100644
--- a/includes/class-wc-order-item-fee.php
+++ b/includes/class-wc-order-item-fee.php
@@ -125,44 +125,44 @@ class WC_Order_Item_Fee extends WC_Order_Item {
 	/**
 	 * Set tax class.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_tax_class( $value ) {
 		if ( $value && ! in_array( $value, WC_Tax::get_tax_classes() ) ) {
-			return $this->error( 'Invalid tax class', $value );
+			$this->throw_exception( 'order_item_fee_invalid_tax_class', __( 'Invalid tax class', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'tax_class', $value );
+		$this->set_prop( 'tax_class', $value );
 	}
 
 	/**
 	 * Set tax_status.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_tax_status( $value ) {
 		if ( in_array( $value, array( 'taxable', 'none' ) ) ) {
-			return $this->set_prop( 'tax_status', $value );
+			$this->set_prop( 'tax_status', $value );
 		} else {
-			return $this->set_prop( 'tax_status', 'taxable' );
+			$this->set_prop( 'tax_status', 'taxable' );
 		}
 	}
 
 	/**
 	 * Set total.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_total( $value ) {
-		return $this->set_prop( 'total', wc_format_decimal( $value ) );
+		$this->set_prop( 'total', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set total tax.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_total_tax( $value ) {
-		return $this->set_prop( 'total_tax', wc_format_decimal( $value ) );
+		$this->set_prop( 'total_tax', wc_format_decimal( $value ) );
 	}
 
 	/**
@@ -170,7 +170,7 @@ class WC_Order_Item_Fee extends WC_Order_Item {
 	 *
 	 * This is an array of tax ID keys with total amount values.
 	 * @param array $raw_tax_data
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_taxes( $raw_tax_data ) {
 		$raw_tax_data = maybe_unserialize( $raw_tax_data );
@@ -180,7 +180,7 @@ class WC_Order_Item_Fee extends WC_Order_Item {
 		if ( ! empty( $raw_tax_data['total'] ) ) {
 			$tax_data['total'] = array_map( 'wc_format_decimal', $raw_tax_data['total'] );
 		}
-		return $this->set_prop( 'taxes', $tax_data );
+		$this->set_prop( 'taxes', $tax_data );
 	}
 
 	/*
diff --git a/includes/class-wc-order-item-product.php b/includes/class-wc-order-item-product.php
index eeffc4f33ce..77250347fec 100644
--- a/includes/class-wc-order-item-product.php
+++ b/includes/class-wc-order-item-product.php
@@ -231,91 +231,91 @@ class WC_Order_Item_Product extends WC_Order_Item {
 	/**
 	 * Set quantity.
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_quantity( $value ) {
 		if ( 0 >= $value ) {
-			return $this->error( 'Quantity must be positive', $value );
+			$this->throw_exception( 'order_item_product_invalid_quantity', __( 'Quantity must be positive', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'quantity', wc_stock_amount( $value ) );
+		$this->set_prop( 'quantity', wc_stock_amount( $value ) );
 	}
 
 	/**
 	 * Set tax class.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_tax_class( $value ) {
 		if ( $value && ! in_array( $value, WC_Tax::get_tax_classes() ) ) {
-			return $this->error( 'Invalid tax class', $value );
+			$this->throw_exception( 'order_item_product_invalid_tax_class', __( 'Invalid tax class', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'tax_class', $value );
+		$this->set_prop( 'tax_class', $value );
 	}
 
 	/**
 	 * Set Product ID
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_product_id( $value ) {
 		if ( 0 >= $value || 'product' !== get_post_type( absint( $value ) ) ) {
-			return $this->error( 'Invalid product ID', $value );
+			$this->throw_exception( 'order_item_product_invalid_product_id', __( 'Invalid product ID', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'product_id', absint( $value ) );
+		$this->set_prop( 'product_id', absint( $value ) );
 	}
 
 	/**
 	 * Set variation ID.
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_variation_id( $value ) {
 		if ( 0 >= $value || 'product_variation' !== get_post_type( absint( $value ) ) ) {
-			return $this->error( 'Invalid product ID', $value );
+			$this->throw_exception( 'order_item_product_invalid_variation_id', __( 'Invalid variation ID', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'variation_id', absint( $value ) );
+		$this->set_prop( 'variation_id', absint( $value ) );
 	}
 
 	/**
 	 * Line subtotal (before discounts).
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_subtotal( $value ) {
-		return $this->set_prop( 'subtotal', wc_format_decimal( $value ) );
+		$this->set_prop( 'subtotal', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Line total (after discounts).
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_total( $value ) {
-		return $this->set_prop( 'total', wc_format_decimal( $value ) );
+		$this->set_prop( 'total', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Line subtotal tax (before discounts).
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_subtotal_tax( $value ) {
-		return $this->set_prop( 'subtotal_tax', wc_format_decimal( $value ) );
+		$this->set_prop( 'subtotal_tax', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Line total tax (after discounts).
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_total_tax( $value ) {
-		return $this->set_prop( 'total_tax', wc_format_decimal( $value ) );
+		$this->set_prop( 'total_tax', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set line taxes.
 	 * @param array $raw_tax_data
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_taxes( $raw_tax_data ) {
 		$raw_tax_data = maybe_unserialize( $raw_tax_data );
@@ -327,13 +327,13 @@ class WC_Order_Item_Product extends WC_Order_Item {
 			$tax_data['total']    = array_map( 'wc_format_decimal', $raw_tax_data['total'] );
 			$tax_data['subtotal'] = array_map( 'wc_format_decimal', $raw_tax_data['subtotal'] );
 		}
-		return $this->set_prop( 'taxes', $tax_data );
+		$this->set_prop( 'taxes', $tax_data );
 	}
 
 	/**
 	 * Set variation data (stored as meta data - write only).
 	 * @param array $data Key/Value pairs
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_variation( $data ) {
 		foreach ( $data as $key => $value ) {
@@ -345,11 +345,11 @@ class WC_Order_Item_Product extends WC_Order_Item {
 	/**
 	 * Set properties based on passed in product object.
 	 * @param WC_Product $product
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_product( $product ) {
 		if ( ! is_a( $product, 'WC_Product' ) ) {
-			return $this->error( 'Invalid product', $product );
+			$this->throw_exception( 'order_item_product_invalid_product', __( 'Invalid product', 'woocommerce' ) );
 		}
 		$this->set_product_id( $product->get_id() );
 		$this->set_name( $product->get_title() );
diff --git a/includes/class-wc-order-item-shipping.php b/includes/class-wc-order-item-shipping.php
index 816404a8193..e2aa57cc9b6 100644
--- a/includes/class-wc-order-item-shipping.php
+++ b/includes/class-wc-order-item-shipping.php
@@ -114,7 +114,7 @@ class WC_Order_Item_Shipping extends WC_Order_Item {
 	/**
 	 * Set order item name.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_name( $value ) {
 		return $this->set_method_title( $value );
@@ -123,37 +123,37 @@ class WC_Order_Item_Shipping extends WC_Order_Item {
 	/**
 	 * Set code.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_method_title( $value ) {
-		return $this->set_prop( 'method_title', wc_clean( $value ) );
+		$this->set_prop( 'method_title', wc_clean( $value ) );
 	}
 
 	/**
 	 * Set shipping method id.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_method_id( $value ) {
-		return $this->set_prop( 'method_id', wc_clean( $value ) );
+		$this->set_prop( 'method_id', wc_clean( $value ) );
 	}
 
 	/**
 	 * Set total.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_total( $value ) {
-		return $this->set_prop( 'total', wc_format_decimal( $value ) );
+		$this->set_prop( 'total', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set total tax.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_total_tax( $value ) {
-		return $this->set_prop( 'total_tax', wc_format_decimal( $value ) );
+		$this->set_prop( 'total_tax', wc_format_decimal( $value ) );
 	}
 
 	/**
@@ -161,7 +161,7 @@ class WC_Order_Item_Shipping extends WC_Order_Item {
 	 *
 	 * This is an array of tax ID keys with total amount values.
 	 * @param array $raw_tax_data
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_taxes( $raw_tax_data ) {
 		$raw_tax_data = maybe_unserialize( $raw_tax_data );
@@ -173,13 +173,12 @@ class WC_Order_Item_Shipping extends WC_Order_Item {
 		}
 		$this->set_prop( 'taxes', $tax_data );
 		$this->set_total_tax( array_sum( $tax_data['total'] ) );
-		return true;
 	}
 
 	/**
 	 * Set properties based on passed in shipping rate object.
 	 * @param WC_Shipping_Rate $tax_rate_id
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_rate( $shipping_rate ) {
 		$this->set_method_title( $shipping_rate->label );
@@ -187,7 +186,6 @@ class WC_Order_Item_Shipping extends WC_Order_Item {
 		$this->set_total( $shipping_rate->cost );
 		$this->set_taxes( $shipping_rate->taxes );
 		$this->set_meta_data( $shipping_rate->get_meta_data() );
-		return true;
 	}
 
 	/*
diff --git a/includes/class-wc-order-item-tax.php b/includes/class-wc-order-item-tax.php
index 2d5526fcafd..c88d3bf3bba 100644
--- a/includes/class-wc-order-item-tax.php
+++ b/includes/class-wc-order-item-tax.php
@@ -85,7 +85,7 @@ class WC_Order_Item_Tax extends WC_Order_Item {
 	/**
 	 * Set order item name.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_name( $value ) {
 		return $this->set_rate_code( $value );
@@ -94,68 +94,67 @@ class WC_Order_Item_Tax extends WC_Order_Item {
 	/**
 	 * Set item name.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_rate_code( $value ) {
-		return $this->set_prop( 'rate_code', wc_clean( $value ) );
+		$this->set_prop( 'rate_code', wc_clean( $value ) );
 	}
 
 	/**
 	 * Set item name.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_label( $value ) {
-		return $this->set_prop( 'label', wc_clean( $value ) );
+		$this->set_prop( 'label', wc_clean( $value ) );
 	}
 
 	/**
 	 * Set tax rate id.
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_rate_id( $value ) {
-		return $this->set_prop( 'rate_id', absint( $value ) );
+		$this->set_prop( 'rate_id', absint( $value ) );
 	}
 
 	/**
 	 * Set tax total.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_tax_total( $value ) {
-		return $this->set_prop( 'tax_total', wc_format_decimal( $value ) );
+		$this->set_prop( 'tax_total', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set shipping_tax_total
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_tax_total( $value ) {
-		return $this->set_prop( 'shipping_tax_total', wc_format_decimal( $value ) );
+		$this->set_prop( 'shipping_tax_total', wc_format_decimal( $value ) );
 	}
 
 	/**
 	 * Set compound
 	 * @param bool $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_compound( $value ) {
-		return $this->set_prop( 'compound', (bool) $value );
+		$this->set_prop( 'compound', (bool) $value );
 	}
 
 	/**
 	 * Set properties based on passed in tax rate by ID.
 	 * @param int $tax_rate_id
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_rate( $tax_rate_id ) {
 		$this->set_rate_id( $tax_rate_id );
 		$this->set_rate_code( WC_Tax::get_rate_code( $tax_rate_id ) );
 		$this->set_label( WC_Tax::get_rate_code( $tax_rate_id ) );
 		$this->set_compound( WC_Tax::get_rate_code( $tax_rate_id ) );
-		return true;
 	}
 
 	/*
diff --git a/includes/class-wc-order-item.php b/includes/class-wc-order-item.php
index 5b1e7731c77..0b84b63c73a 100644
--- a/includes/class-wc-order-item.php
+++ b/includes/class-wc-order-item.php
@@ -152,37 +152,37 @@ class WC_Order_Item extends WC_Data implements ArrayAccess {
 	/**
 	 * Set ID
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_id( $value ) {
-		return $this->set_prop( 'id', absint( $value ) );
+		$this->set_prop( 'id', absint( $value ) );
 	}
 
 	/**
 	 * Set order ID.
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_order_id( $value ) {
-		return $this->set_prop( 'order_id', absint( $value ) );
+		$this->set_prop( 'order_id', absint( $value ) );
 	}
 
 	/**
 	 * Set order item name.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_name( $value ) {
-		return $this->set_prop( 'name', wc_clean( $value ) );
+		$this->set_prop( 'name', wc_clean( $value ) );
 	}
 
 	/**
 	 * Set order item type.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	protected function set_type( $value ) {
-		return $this->set_prop( 'type', wc_clean( $value ) );
+		$this->set_prop( 'type', wc_clean( $value ) );
 	}
 
 	/*
diff --git a/includes/class-wc-order-refund.php b/includes/class-wc-order-refund.php
index 4e79dded5ef..dfb28d5455c 100644
--- a/includes/class-wc-order-refund.php
+++ b/includes/class-wc-order-refund.php
@@ -115,10 +115,10 @@ class WC_Order_Refund extends WC_Abstract_Order {
 	/**
 	 * Set refunded amount.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_amount( $value ) {
-		return $this->set_prop( 'amount', wc_format_decimal( $value ) );
+		$this->set_prop( 'amount', wc_format_decimal( $value ) );
 	}
 
 	/**
@@ -141,10 +141,10 @@ class WC_Order_Refund extends WC_Abstract_Order {
 	/**
 	 * Set refund reason.
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_reason( $value ) {
-		return $this->set_prop( 'reason', $value );
+		$this->set_prop( 'reason', $value );
 	}
 
 	/**
@@ -159,10 +159,10 @@ class WC_Order_Refund extends WC_Abstract_Order {
 	/**
 	 * Set refunded by.
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_refunded_by( $value ) {
-		return $this->set_prop( 'refunded_by', absint( $value ) );
+		$this->set_prop( 'refunded_by', absint( $value ) );
 	}
 
 	/**
diff --git a/includes/class-wc-order.php b/includes/class-wc-order.php
index ecc5b2d9000..1e92e43def2 100644
--- a/includes/class-wc-order.php
+++ b/includes/class-wc-order.php
@@ -815,208 +815,208 @@ class WC_Order extends WC_Abstract_Order {
 	/**
 	 * Set order_key.
 	 * @param string $value Max length 20 chars.
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_order_key( $value ) {
-		return $this->set_prop( 'order_key', substr( $value, 0, 20 ) );
+		$this->set_prop( 'order_key', substr( $value, 0, 20 ) );
 	}
 
 	/**
 	 * Set customer_id
 	 * @param int $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_customer_id( $value ) {
-		return $this->set_prop( 'customer_id', absint( $value ) );
+		$this->set_prop( 'customer_id', absint( $value ) );
 	}
 
 	/**
 	 * Set billing_first_name
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_first_name( $value ) {
-		return $this->set_prop( 'billing', 'first_name', $value );
+		$this->set_prop( 'billing', 'first_name', $value );
 	}
 
 	/**
 	 * Set billing_last_name
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_last_name( $value ) {
-		return $this->set_prop( 'billing', 'last_name', $value );
+		$this->set_prop( 'billing', 'last_name', $value );
 	}
 
 	/**
 	 * Set billing_company
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_company( $value ) {
-		return $this->set_prop( 'billing', 'company', $value );
+		$this->set_prop( 'billing', 'company', $value );
 	}
 
 	/**
 	 * Set billing_address_1
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_address_1( $value ) {
-		return $this->set_prop( 'billing', 'address_1', $value );
+		$this->set_prop( 'billing', 'address_1', $value );
 	}
 
 	/**
 	 * Set billing_address_2
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_address_2( $value ) {
-		return $this->set_prop( 'billing', 'address_2', $value );
+		$this->set_prop( 'billing', 'address_2', $value );
 	}
 
 	/**
 	 * Set billing_city
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_city( $value ) {
-		return $this->set_prop( 'billing', 'city', $value );
+		$this->set_prop( 'billing', 'city', $value );
 	}
 
 	/**
 	 * Set billing_state
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_state( $value ) {
-		return $this->set_prop( 'billing', 'state', $value );
+		$this->set_prop( 'billing', 'state', $value );
 	}
 
 	/**
 	 * Set billing_postcode
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_postcode( $value ) {
-		return $this->set_prop( 'billing', 'postcode', $value );
+		$this->set_prop( 'billing', 'postcode', $value );
 	}
 
 	/**
 	 * Set billing_country
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_country( $value ) {
-		return $this->set_prop( 'billing', 'country', $value );
+		$this->set_prop( 'billing', 'country', $value );
 	}
 
 	/**
 	 * Set billing_email
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_email( $value ) {
 		if ( $value && ! is_email( $value ) ) {
-			return $this->error( 'Invalid email address', $value );
+			$this->throw_exception( 'order_invalid_billing_email', __( 'Invalid order billing email address', 'woocommerce' ) );
 		}
-		return $this->set_prop( 'billing', 'email', sanitize_email( $value ) );
+		$this->set_prop( 'billing', 'email', sanitize_email( $value ) );
 	}
 
 	/**
 	 * Set billing_phone
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_billing_phone( $value ) {
-		return $this->set_prop( 'billing', 'phone', $value );
+		$this->set_prop( 'billing', 'phone', $value );
 	}
 
 	/**
 	 * Set shipping_first_name
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_first_name( $value ) {
-		return $this->set_prop( 'shipping', 'first_name', $value );
+		$this->set_prop( 'shipping', 'first_name', $value );
 	}
 
 	/**
 	 * Set shipping_last_name
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_last_name( $value ) {
-		return $this->set_prop( 'shipping', 'last_name', $value );
+		$this->set_prop( 'shipping', 'last_name', $value );
 	}
 
 	/**
 	 * Set shipping_company
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_company( $value ) {
-		return $this->set_prop( 'shipping', 'company', $value );
+		$this->set_prop( 'shipping', 'company', $value );
 	}
 
 	/**
 	 * Set shipping_address_1
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_address_1( $value ) {
-		return $this->set_prop( 'shipping', 'address_1', $value );
+		$this->set_prop( 'shipping', 'address_1', $value );
 	}
 
 	/**
 	 * Set shipping_address_2
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_address_2( $value ) {
-		return $this->set_prop( 'shipping', 'address_2', $value );
+		$this->set_prop( 'shipping', 'address_2', $value );
 	}
 
 	/**
 	 * Set shipping_city
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_city( $value ) {
-		return $this->set_prop( 'shipping', 'city', $value );
+		$this->set_prop( 'shipping', 'city', $value );
 	}
 
 	/**
 	 * Set shipping_state
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_state( $value ) {
-		return $this->set_prop( 'shipping', 'state', $value );
+		$this->set_prop( 'shipping', 'state', $value );
 	}
 
 	/**
 	 * Set shipping_postcode
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_postcode( $value ) {
-		return $this->set_prop( 'shipping', 'postcode', $value );
+		$this->set_prop( 'shipping', 'postcode', $value );
 	}
 
 	/**
 	 * Set shipping_country
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_shipping_country( $value ) {
-		return $this->set_prop( 'shipping', 'country', $value );
+		$this->set_prop( 'shipping', 'country', $value );
 	}
 
 	/**
 	 * Set the payment method.
 	 * @param string $payment_method Supports WC_Payment_Gateway for bw compatibility with < 2.7
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_payment_method( $payment_method = '' ) {
 		if ( is_object( $payment_method ) ) {
@@ -1028,88 +1028,87 @@ class WC_Order extends WC_Abstract_Order {
 		} else {
 			$this->set_prop( 'payment_method', $payment_method );
 		}
-		return true;
 	}
 
 	/**
 	 * Set payment_method_title
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_payment_method_title( $value ) {
-		return $this->set_prop( 'payment_method_title', $value );
+		$this->set_prop( 'payment_method_title', $value );
 	}
 
 	/**
 	 * Set transaction_id
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_transaction_id( $value ) {
-		return $this->set_prop( 'transaction_id', $value );
+		$this->set_prop( 'transaction_id', $value );
 	}
 
 	/**
 	 * Set customer_ip_address
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_customer_ip_address( $value ) {
-		return $this->set_prop( 'customer_ip_address', $value );
+		$this->set_prop( 'customer_ip_address', $value );
 	}
 
 	/**
 	 * Set customer_user_agent
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_customer_user_agent( $value ) {
-		return $this->set_prop( 'customer_user_agent', $value );
+		$this->set_prop( 'customer_user_agent', $value );
 	}
 
 	/**
 	 * Set created_via
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_created_via( $value ) {
-		return $this->set_prop( 'created_via', $value );
+		$this->set_prop( 'created_via', $value );
 	}
 
 	/**
 	 * Set customer_note
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_customer_note( $value ) {
-		return $this->set_prop( 'customer_note', $value );
+		$this->set_prop( 'customer_note', $value );
 	}
 
 	/**
 	 * Set date_completed
 	 * @param string $timestamp
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_date_completed( $timestamp ) {
-		return $this->set_prop( 'date_completed', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
+		$this->set_prop( 'date_completed', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
 	}
 
 	/**
 	 * Set date_paid
 	 * @param string $timestamp
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_date_paid( $timestamp ) {
-		return $this->set_prop( 'date_paid', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
+		$this->set_prop( 'date_paid', is_numeric( $timestamp ) ? $timestamp : strtotime( $timestamp ) );
 	}
 
 	/**
 	 * Set cart hash
 	 * @param string $value
-	 * @return bool|WP_Error Returns success true or false/WP Error on failure.
+	 * @throws WC_Data_Exception
 	 */
 	public function set_cart_hash( $value ) {
-		return $this->set_prop( 'cart_hash', $value );
+		$this->set_prop( 'cart_hash', $value );
 	}
 
 	/*