Consumable data objects are transferred from a source server to a vehicle server. The availability of a first data communications link from the source server to a vehicle server is detected and a count of consumable data objects stored on the vehicle server is generated. If the first data communications link is detected, the count is transmitted to the source server over the link. An identifier of the vehicle server is derived from the first data communications link, and this identifier is associated with the count. A consumable data object replenishment count is generated based upon an evaluation of the count in relation to historic use data derived from past counts.