I'm living this dream right now. I'm 56, and working as head wrench at a local shop. I worked over 30 years in a high stress corporate job, traveling constantly, until one Friday night coming home from yet another business trip I realized that if Things didn't change I was going to have a breakdown. I've always been a bike geek, so I went to UBI in Portland to get "certified" , and have been doing what I love doing everyday for the past 3 years. Sure the money isn't the best, but the trade-off in happiness and mental well being is more than worth it.
And yes, a tool addiction can be expensive!