I was thinking about this question today as someone used our work printer for some personal stuff.
As for me, I am printing little things that I would say make it worth it. I’ve printed lens adapters for my camera for example. That’s worth a good 14 to 30 bucks per print. My most favorite photo was with an adapted lens that came from a projector. I also printed IEMs and those things are worth it. Listening to music is second to none on those things. Plus I printed the same shell but for ear protection and again the fit is perfect and sure there’s post processing to get smooth surfaces but in the end it looks like a professional made it. So I think 3d printers are worth it.
I find mine worth it. So many things I’ve had to replace entirely just because some random plastic part would break, but I can just replace the broken plastic part now. Custom light switch and electrical outlet covers, custom keyboard key caps, case shells for various things (like phones and controllers), not to mention all the unique things others have engineered specifically for 3D printing like the Lego-like organizing containers that are infinitely scalable.
I love it.
Infinigrid is your friend