I started out cutting and threading iron pipe and graduated to sweating copper pipe as my norm for in residential applications.
I gave a ho-hum to Pex (cross-linked polyethylene) probably due to the massive failure of Quest pipe (polybutylene 1978-1996) Quest was the predecessor of Pex.
Now, given time it has proven it's self, it is probably going to be around from now on.
It has it's strengths and weaknesses much like the copper pipe I prefer.
For industrial applications HDPE (high-density polyethylene) has taken the trade by storm, much like Pex has in residential applications. HDPE is now used where once PVC, Stainless and even Cast Iron pipe once ruled the roost.
My experience has been from hands on to project engineering oversight.
I have a plumber neighbor who today has a couple of hundred trucks on the road daily.
His crews are pretty young, few have a clue of how to sweat copper pipe, I doubt most would even recognize let alone know how to operate a pipe threader if one was in front of them. PEX rules their world, the plumbing trade involving installation of copper or iron pipe is lost.
