I have an appliance repair business. I charge for labor and parts. I mark up my parts a flat percentage. How do I respond when a customer wants me to breakdown the cost of labor vs parts? Because I know what they are really trying to do is see if they can find the part cheaper on the internet.
I have a friend who does that as well. He also has a form explaining that if the customer supplied part gets broken during installation, he will not replace it at his expense.