The durability of projector

Mitsubishi DLP's tend to have very few reported issues in this forum compared to many other brands. We don't have all the data, but the Mitsubishi hc4000 definitely appears to be one of the most reliable since it has a long product life-cycle with such few issues and almost no breakdowns reported in the thread (only a few out of thousands). DLP projectors will generally have the ability to last longer since they do not have panel degradation like the other two techs, but their color wheels can still break or they can have a power issue. That said, this is where I would put my bet if I were going for longevity.

Longest life projector with "zero" maintenance is likely an LED DLP unit. No user replaceable bulb, no color wheel. So no large scale moving parts.. just the DLP DMD which is usually very reliable.

Rps13
I'm not exactly disagreeing with you, but we don't know yet how well LED PJ's hold up, they have just come out the last year or 2. Maybe they will turn out to be the best, but they are still not very bright and 1080p in LED is not out yet, but should be soon, and then we will have to wait a few years to see if they really last. I agree in principle but it's theory. Now from the stuff that has been out the last 5-10 years, what has held up the BEST is interesting question, something maintenance free , except for changing the bulbs, right?. I guess we have to look to forum rooms , not sure there is a graph on it, maybe there is, I don't know.

My only issue with DLP LED is that many of the cheaper ones have fairly poor build quality and poor contrast. If we are talking sub $1,500 projectors with good PQ, then I stand by the fact that the Mits hc4000 has the fewest reported issues in this forum overall (and god knows I spend too much time reading posts in this forum). The LED lamps will last longer, but something else might go wrong, theoretically though they would be the most reliable once they are seasoned and 1080p LED is affordable, but it's not yet and they aren't.

The hc4000u might be very reliable but I had to returned my hc3800 twice, so there is clearly model variation within the same family.

To me, lamps are the weakest links, so LED is a positive direction.

The other option is have a "good" company undercut the competition and come out with "cheap and good" bulbs that cost 50 dollars.
But I wouldn't count on that, but if DLP wants to continue and Thrive, cheap bulb replacement would make these things sell, because bulb life is a turn off if the bulb costs 250 dollars to replace and only lasts 2,000 hours. Compared to 50,000 hours on HDTV.

The bulb for my current DLP projector costs about 100 Euro and last for 5000 hours. Thats not too bad. It translates to a lifetime of 20 years at my current usage rate. Very likely the projector will be obsolete, dead or sold before the end of the life of the bulb.