Re: Replacement cycle....
"5-6 years seems very low!"
Remember that these units are on some 8 hours a day. Many are hard-powered down (switched mains circuits) at the end of the day, which some power supplies don't like, others are left powered-up so go into standby when the signal disappears. As I said, most of the failures are power supplies and fortunately for us, most of the power supplies are external 12V bricks so replacement is very easy. The actual display part of the monitor maybe lasts a bit longer but our 17" Neovos (not touchscreen, but must have S-video inputs) do seem to suffer from backlight loss and screen fade quite a lot. Neovo is not a cheap brand.
You think that's bad, just consider the fact that all bar five of the originally-installed 30-ish projectors here were LCD models. It seems that many people aren't aware that LCD panels and their associated dichroic colour filters have expected lifespans in the 4,000 - 8,000 hour range. In fact the original projectors here had a manufacturer listed lifespan of 4,500 hours. In our terms that's not even two years before they need replacing!
Turns out that the cost of replacing the "optical block" in these original projectors was significantly higher even if DIY'd than the cost of buying a nice new Panasonic DLP with higher brightness, higher availability (two lamps), twice or three times the lamp life (so lower running costs) and a rated lifespan of around 20,000 hours.
Sorry, rather far OT there ;-)
As for using reconditioned monitors, it's a possibility for the 17" units (fortunately we can still - just - get 19" units to the same spec) but it's not a long-term solution. Long term solutions involve ripping the display out and starting again (new setwork, new content, new software) which isn't going to happen in the current "financial climate".