When car is taken for service the service technician gives an estimate of cost and you sign the paper and come back home. After an hour or two you will receive a call to inform that an expensive major part needs replacement and you have the option of either going back to service centre to check or accept it and tell them to do the job. Thus you end up paying a very high service cost in spite of fact that the car was driven to service centre by you and there was no serious issue apart from routine service. This has been my personal experience on number of occasions.