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.
Break it down for them and let them know. Part cost is researching what part is needed, ordering the parts from a trusted source (No Amazon knockoff), picking up the part, warrantying the part, and having an experienced person to install it. They are paying for a service and part of that service is knowing what part went wrong when it breaks. If it was so easy and cheap then they should have done it themselves. They are not paying just for the time it takes to fix an appliance they are paying for your years of knowledge of knowing how to fix it.