It just occurred to me that I've never taken my bike into a shop for a "tune-up". My question is, what exactly is involved in a "tune-up"? When I walk into a shop and say I want a tune-up, what do they do?
I change my oil at a good interval, clean and lube the chain regularly, oil/grease parts as needed, top-off and flush fluids as required. Am I missing something obvious?