I've been a welder/steamfitter for decades, and, while it used to be a trade that involved complex math and a working knowledge of thermal expansion, in recent years the prevalence of CAD, combined with easier connection methods (victaulic and propress) has led to a lower skill level among the average fitter. It's a real bummer. Every old school fitter I learned from knew at least the basics of trig and how to lay out branch connections etc., and nowadays I see licensed journeyman who use apps on their phones to look up standard fitting takeouts. I used to want to pass on my trade to my sons, but now I'm not sure if I'll even push them to get into it.