If a dumb-ass like me can self-learn at this, anybody can. The actual printing of other peoples stuff you download is dead easy, that takes less than a week to figure out the basics and there is TONS of help on different facebook or MeWe groups. It's once you get into designing your own stuff that the REAL curve kicks in. Get very used to making mistakes, re-doing things 3 or 4 times to get it right, and wasting about 1/2 of the filament you buy (I am working on a shredder right now to start re-cycling the stuff). Chainsaw chain in a spiral around a 30mm drum.
This is my latest for a client, and Ill put them up for general sale too. Gimbled/ ball-jointed beer can holder for a push-mower. You might get sideways, but your beer wont !! 15 hours and about 3 bucks worth of filament to make it and I figure on 3 prototypes to get it torture tested and perfect. Once I do I'll publish the print file and let it generate some income forever.