Originally Posted by Sixty Fiver

Quote them the full price of what it will cost to make the bike right and then sell them a new one.

In my own little shop I will usually charge folks an hour minimum for a minor service inspection as when I go over the bike I will make minor adjustments to things like brakes and derailers, check the tyres, and lube the chain. If time allows I will even do minor truing of wheels.

In a busy shop you need to set the rules and be firm in letting people know that there were people there before them and for as much as one might like, other people were there first and expect to have their bikes ready.

There are exceptions to every rule... if you have the time and can correct something in a few minutes and allow someone to get on with their riding day it builds good will and will draw customers.