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 print all kinds of usefull stuff.
Custom installation panel for after market navigator/media center for my car, upholstery fasteners for the same, custom panels for usb button box, cable organizers for lan cabling, newspaper reading stand, you name it.
Might not be financially feasible, but it’s fun.