I've worked at a bikeshop when I was a kid. That's long ago so my experience is dated, but here is my takeaway: There are good customers. There are also lots of not so good customers and there are a lot of jerks. People want their bikes ready yesterday, can't imagine why after they neglected their bikes for three years it can't be finished in a few hours.

And today they are taken aback by any reasonable hourly rate because a new bike from China costs less than a few hours of your work. Good luck! Oh, and if you really follow through on this make sure you copy Sheldon's pages just in case they ever go down, you'll have an edge over the rest.