I plumb a little bit, often with about 6+ trades involved. Takes a lot of imagination, and ingenuity, Let me tell you.
With larger pipe in dirtier places than the average plumber. Septics, filtered streambed hydro pickups [and notice the average winter flow after the completion] And finally, a few of my "tools" - you should see what concoction of pipes is under all that beautiful USA made iron! And just for "filler time" Built the house too. No subs.