In Salesforce B2C Commerce, site preferences allow customization and configuration of various site-specific settings, which can be managed independently across different regional sites on the same instance. By creating a new custom preference under the Site Preference object type, developers can introduce a setting that specifies the number of products eligible for gift wrapping per order for each specific site. This approach provides the flexibility needed to adjust these numbers independently for the U.S. and European markets as required by the business logic. Such preferences are accessed and modified through the Business Manager, ensuring that business users can easily update them without needing further code deployment. This solution aligns with Salesforce B2C Commerce's best practices for managing site-specific behaviors and configurations without hardcoding values, thereby maintaining scalability and manageability across multiple market-specific sites.