With some machines they are as simple as a regular printer. Load file and print.... replacing filaments is ez as loading a tight welder.I understand, figured id ask. I honestly feel way out of my league when I think of 3d printing. I have so many hobbies... Im on the fence about picking up a tig welder and some vacuum bagging equipment as we speak. I already do a ton of glass work on boats and surf boards, and a bit on skis. Im thinking im going to push that horizon because I really enjoy it.