A method of maintaining a status of a product item is provided. The product item includes an associated interface surface which has coded data including a plurality of coded data portions indicative of the product item's identity. The method includes, in a sensing device, sensing at least one coded data portion, generating indicating data indicative of the product item identity therefrom, and transferring the indicating data to a computer system. The computer system is responsive to the indicating data to update product status information stored in a data store. The interface surface includes at least one region, including coded data indicative of an identity of the at least one region. The method further includes, in the sensing device, sensing the coded data disposed within the at least one region, and generating, using the sensed coded data, indicating data indicative of the region identity.