WooCommerce customers and sessions

Use this skill whenever code touches the active shopper, account profile, cart-flow state, or Store API session.

The critical distinction

WC()->customer is created in session mode:

new WC_Customer( get_current_user_id(), true );

Its data store is WC_Customer_Data_Store_Session. Calling WC()->customer->save() updates the WooCommerce session for both guests and logged-in users; it does not persist account fields to user meta.

To edit a registered customer's durable profile, load a separate non-session object: