Many years ago, our overhead garage door mechanism broke. We called a locally owned company, and the owner came over to take a look. He diagnosed the problem and told my husband that, while he could fix it and charge us, my husband could probably buy a part for a couple of bucks and fix it himself. He gave us the part number, didn't charge us and went on his way.
My husband attempted to fix the garage door himself, and it just didn't seem to work. He called the original company and asked if they had any suggestions, and if not, could we get a service call? The owner said he was going to be in the neighborhood later, so he came by to take a look. He figured out the problem, walked my husband through the fix and did not charge us a thing.
Suffice to say, we hired them to install a new door when it was time. We called them when someone (cough cough) decided to try to back out of the garage without, um, actually opening the garage door. We recommend them to everyone, and we cringe when we see some of the bigger names working on neighbors' garage doors. They're awesome.