There is a record of every car, truck, etc., belonging to each client, so you will have a history of all services performed to each one.
As jobs usually have several stages, the customers can always see the status of their vehicle repair, because technicians or mechanics will update the order as the work progresses. Thus, the clients does not have to call periodically to your company asking about the work, because they can enter directly to the system and verify the job, comments, etc.
This means a greater customer loyalty and satisfaction, as it is desirable that vehicles be always reviewed by the same people and the clients should not to control or remember which services will have been made to their vehicles.