For example, if your engine is stalling and it's noted that you had all new fuel filters installed just a few thousand miles back, the technician can probably rule out filter inspection during the diagnostic steps. Remember, no one knows your vehicle like you do. The technician may be coming into the project cold if he or she has never seen the vehicle. Those written records you have available can bring that technician up to speed in a hurry regarding the vehicle's past history and that knowledge can speed the repair. It's likely the repair people will be spending time inside your vehicle if that's the best way to access the repairs.
Time is money for a service center.
Make sure the area involved in the repair is clear and ready for work. If it's a water pump under a sink that's being worked on, unload the cabinet so the pump and its plumbing and wiring are exposed and accessible. If they need to get to a motorhome's engine, remove any assorted hardware you have piled on the doghouse or around its edges. If the technician needs to do these things before starting work, it takes time and adds to your bill. This step can also avoid misunderstandings later on.