A&P Mechanics are considered Jacks of all trades by many (I didn't make that up). That doesn't mean they all are, or that only A&P'school are, but, that their diverse training sets them up to be, and their experiences in the field set them apart. Could someone else be as good or a better mechanic sure. I have been unimpressed by electrical contract companies a couple times, and they were only dealing with one trade. Just an example; We had an addition put on our home and had a door jam switch installed for the walk-in closet. About a month after completion the switch started making arcing sounds and started smoking. I called the contractor and the electrical contractor came out and replaced the switch. About a month later it happened again. They changed the switch again. That time, I asked the guy if I could see the old one. It was a 12v switch... seriously. I told the guy, and his response was "thats the one they give me." Well, he made a call, and went and got the right switch and it's worked for over twenty years now.