That will depend on whether "X" is an amount that the shop can survive on. The perfect formula is a combination of service that the customer appreciates and price that the owner can live on. Any one of those options could be a good or bad one. For instance, if the shop does too much, it can actually lose money on the deal. How many deals can they afford before they go out of business? On the other hand, if the shop does too little, how long before the customer looks elsewhere to find a better value? Finding the happy middle ground is the difficult part.