I worked in a shop for 10 years. It was a learning experience. I would not bring my bike in to let someone "learn on". If it was a simple detail that had a minimal risk of them screwing up my bike (tire , tube change), maybe I would. If it was something more technical and had a greater risk of damage ( frame prep, cut fork)....no way. They would not be able to correct their damage to my bike. I have too much personal energy invested in my bike to let other people say "my bad" and offer a refund for their services. On that note, I am still looking for a good mechanic to refer other people to. I still enjoy wrenching, but I won't do it for money. I like to take my time and do it right.