Locally, all the bike shops (with the exception of only 1 out of 8) hire high school kids to work as mechanics every summer. Not one of them knows more than how to screw a bolt in! And the advice they give! "Oh, Shimano doesn't make single cogs anymore", or "I hear that Tubasti is the best tubular glue you can buy". Give me a break!!!!
When I worked at a bike shop (I was 16), the owner kept me busy with flat repairs, wheel truing, chain replacements, and a lot of shop cleaning. He did all the more delicat mechanical work. a friend of mine, however, worked at one of the local shops about 5 years ago, when he was 17. They had him building wheels and assembling bikes from kits (he had to do 4 or 5 an hour!!!). He now realises that he didn't know squat back then, and he wonders how many of his "wheelbuilds" have failed, knowing now what he didn't know then.
No, I'm not sorry about what I said, at least as it concerns my local shops. A mechanic in any one of them starts at $6.50/hour. What kind of quality are you going to get for that kind of pay? Part of the reason that people consider bikes as toys is because the bike shop proprieters do, too.