Why are you pay when you can do it yourself

Why you don’t ask yourself can I know this fault myself when your car check engine light comes out or when your car trouble you before you call near mechanic or car dealer. If you call them they will charge you to use their scan tool or diagnostic tool to diagnosis your car and charge you again after they repair your car but if you have a good scan tool or diagnostic tool to can perform this yourself maybe it can be something you can repair yourself and save your money. If you don’t have any scan tool or diagnostic tool you buy one for yourself.