I'm a self-employed offset printer. Not only do I have to have the color judgement of PE and the guys at the Big Place, but I have to be a rocket scientist of a repairman. Because nobody else is going to do it--I don't make enough money to get service guys to fix things. And it would be sort of stupid--since I've seen the kind of work some "factory-trained techs" do, and have had to fix it right after them. Back in the 80's my employer paid to have a tech flown in all the way from Germany and he worked on that big Koenig-Bauer press for 3 weeks. After he left that was the water-slingingest piece of junk I ever saw. And if we're talking about a genuine German technician, then that proves nobody else could not have done better.
The trick to working on something is to get ALL the facts, THEN work carefully and methodically. Anything else is just knucklehead work, which I do not tolerate.