One day I'll put the 7 years of LBS work I did to text... oh man the stories.

But for now...

We always replaced a punctured tube. We always (in a nice way) told the customer that we aimed for $75/hr labour on any work we did. Did they want the new tube or pay me to watch glue dry? I think the charge was CAN$12. Also, it sucks when the patch fails and the customer is back for a no-charge repair to make it right. So, do it right with a new tube.

We used to have races in the back to see how fast we could change a tube from bike on the floor, to the hooks, change the flat and get the bike back on the floor. IIRC, this guy Steve could do it in under 120 seconds (and that included the inspection of the tire for the penetrant).

Why do people have the LBS do the repair? Usually they don't have the tools or they live in an apartment and just don't want to deal with a grimy rear wheel.