Union apprenticeship sign-ups near Boise

I heard of an apprenticeship with paid on-the-job training for people changing careers. I would rather hear the honest version than the polite one. Applications close in 4 weeks. What do you wish you had known?

You earn while you learn, but the first year is tight. Plan your budget carefully.

The aptitude test was mostly maths and reading a diagram. Free practice tests online were enough for me.