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 am also in the ender boat.
95% of my problems went away when I took the thing completely apart (like, further apart than what it comes in the box), and rebuilt it from scratch, making sure every bolt was tight, every moving part was free,corners perfectly cornered, etc.
I think it had just enough factory misalignment and loseness in a few key areas that compounded to cause me tons of headaches.
That, plus a few cheap upgrades (steel bed and better bed springs) really erased almost all the mechanical issues.