When we moved into our new house last year, the garage door was noisy and squealing and didn't work half the time. You'd press and press and press the button on the remote and after a dozen tries, suddenly the door would open. We thought the remote was dying.
Well, Sean figured out what the real problem was. The remote antenna on the unit had been stuck inside the unit and was only getting intermittent signal from the remote. He also lubed up the hinges and put a special low temperature lube on the rail. The door is much quieter now.
I was impressed with his expertise but even more impressed with his ethics. Before he found the covered antenna, he thought we were going to need a new unit with a new remote for around a hundred bucks and we'd already said that was fine. But he was too ethical to keep quiet and let us spend the money once he found the real problem.
Also he spent time showing me how to maintain the door in best condition myself. I appreciated that. But hell, with guys as good, I'd rather just call them.