About 1/2 way through my apprenticeship they mandated 'forced rotation' on the apprentices. If you worked for one contractor for more than 6 months you would get rotated to another contractor. Some of the guys were ticked off, but they also were 'specialized' and didn't know much outside their comfort zone.
I really like going from one place to another. It was like an adventure. New guys, new bosses, new rules and new tricks of the trade.
My first gig was with a company that had maintenance contracts. We were in a baby formula plant. I learned how to run aluminum and also how to do 'picture perfect' work, as that was a big thing on that job.
From there, I went to building the biggest high school in the area. I pulled 35.4 miles of #8 off spools, up three levels to a shiv and from there to a dimmer room and out.
Also, not in any particular order, I got to install pollution control equipment on a coal burning power plant, fire suppression equipment on another, helped build and test conductors at a jet turbine power plant, worked building a line at Keebler where Pop Tarts were made, helped build a jail in the middle of a very cold winter in Baldwin, MI (75 mile drive, one way, that job sucked), went down to work at Mittal #2 in Gary, one of the largest steel mills there is. There are more, and I think I went through a half dozen contractors, at least.
Then, the bottom fell out of the construction business. So I went to work for a residential contractor. I had never run Romex before, so new skills were being learned. The first company went out of business, but at least I learned how to put in a residential service, something that would make me money when I needed it in years to come. Then, a foreman I worked for at a power plant started up a business and asked me to work for him. There were 4 of us, and for a couple years things were good. Our gigs, beside light commercial and res work, was putting in ATS units for Verizon all over the state. We were a sub for a long standing local communications company. Verizon folded, stopped all our work, and now we were down to pretty much part time and running electrical stuff for the comm company. That went out of business. And so on. I don't even try to list all that stuff on a resume.
Every place I worked I learned a different skill set, one I wouldn't have if I stayed at one place. Skill sets include running pipe, reading prints, working with engineers, troubleshooting, working with inspectors, pulling wire, building trapeze and cable tray, operating heavy equipment, installing services, and more.
So, despite my apparent 'instability', the up shot is I don't really need much training to do most work. Most of the time my instructions are 'go see so and so and take care of it' or I get a page or two of prints with circles around stuff I'm supposed to get done.
The last union job I did was doing the refrigeration controls for a 375,000 sq. foot grocery / department store. I get there and it's me and another j-man, the son of one of my former bosses, trying to figure out what we were supposed to be doing. Neither one of us had run refrigeration controls before. EC shows up, leaves one guy behind for one week to 'train' us. From that point on, for 6 months, me and the other j-man never saw anyone from the company except for pay day or when stuff like big tools were moved. No problem. Once we got the gist of things and the EC knew we could read prints, we just built the place. No need for a foreman.
Being an 'electrician' can mean so many things. When hiring, I guess it's important to know who will work out best, the self sufficient guy that can not only work with out much or any training, and is one that is used to going without work for several weeks a year vs. a 'steady' that has only been at one place and is NOT used to going without work? Are you sure you can even provide an environment a steady wants?
Case in point. When I was just out of high school I worked for a cam shaft company that had been around for decades. About 20 years later I had decided that I was sick of driving all over creation as an electrician to work mostly outdoors. I read that the company was hiring for a maint. tech, which is what I had done there years ago. I went on an interview to find out the company was now owned by the Chinese. But they assured me they weren't going anywhere. The pay was OK for a layperson, but not quite what a licensed electrician made. So I didn't consider the job. A year later they moved the entire plant to China and laid off all the people that worked there. Besides those people, consider the small businesses that were hurt by that move. I'll bet at least one electrician from an outside company lost his job because of the move. This was a big place, the place that all Isky, Crane and OEM Ford, GM and MoPar cams were once made.
Today's environment is not the same. It's no longer as important to dedicate yourself to a single employer 'till retirement as it is to be flexible and prepared to lose your job at any time.