I have had a couple of CRT projectors and still have one as my primary viewing device. They don't need maintenance so much, they are VERY reliable in my experience (at least the last generation) but you do need to know how to set them up. It is not hard but it takes a while to learn and a while to setup. Once setup they are really no trouble at all. My Barco 808 was setup over a year ago and I think I have touched up the convergence once since.
I did put new tubes into it when I hung it and so the convergence adjustment was probably due to that as the tubes broke in. The tubes are expensive but you can find deals my 3 new high resolution 8" tubes came from a government surplus auction and cost me all of $200 and my projector cost me $700 not a bad deal at all (the projector was purchased 4+ years ago when prices were much higher). Of course most folks don't want to swap their own tubes so you just buy a good used set with very good tubes. They will probably outlast the useful life of the projecto these days. Used 8" sets are very cheap.