Your shop should be charging "time & materials," not fixed rates, for difficult repairs. I hate to see so many shops and/or mechanics take the hit for bikes that are in terrible shape and improperly maintained. If it takes a qualified mechanic four hours to make a bike work, then the shop should be billing for four hours! If a customer brings in a disgusting bike, you should charge a cleaning fee to get the bike in condition to be serviced. A fastidious mechanic of mine always lamented the dirty bikes by saying, "I bet these customers brush their teeth before they visit the dentist!" And yes, I'm aware of the potential environmental hurdles or costs involved with cleaning bikes in a business environment.

This is what marginalizes the bike industry. Stuff we "throw in for free" to be good guys. Sorry, that's how you run your business into the ground. And people have come to expect stuff be done for free because, "it only took a minute to do!" Well, the reason it "only took a minute" is because you have a trained, paid and insured professional doing the job in a custom workspace designed to expedite repairs that are done with proper and bike-specific tools. Everything adds up to getting thing done efficiently.

Shops shouldn't be penalized for this. It might take decades to change, but it really needs to happen.