The most popular labor guides such as Alldata, Chilton and Mitchell’s purchase repair information from the manufacturers. The factory sets a time for every repair to the vehicle. They come up with most of these labor times by formulation not by actually dismantling the vehicle. This means that some labor times can vary from actual time, but the overall labor time is fairly accurate. The idea is that the more experienced the technician is, the faster the repair time. This is called the technicians efficiency rate and most shops like to see at least 130%, which means the technicians billable time net about 30% profitability. If the technician is given a job that is rated at 10 hours and does the job in 7, then he is available for more work that will overlap that 10 hours. This leads to profit because the technician will also work faster on the 7 hour job. Auto repair shops sell parts and time not repairs, which is why consumers have to be careful when analyzing estimates for repairs. An estimate for repair to your car has very few components, labor time, parts and sales tax. Other fees such as shop supplies, hazardous waste or any other fee is added by the shop to cover a specific cost the shop may incur while performing repairs to your car. These fees however are sometimes abused and are simply added profit.