Reliable mechanics have high rates and long waits everywhere I've lived.

Hell, I've seen some that are so busy that they won't take new customers!

They also select reliable customers by their rates. People who will bring in their car on time, and pay the bill on time, and not feign outrage when you hand them the bill, and not try to nickel and dime you by providing their own parts or or asking you to do work based on their own diagnosis of the problem.