Unfortunately no one site says all the same things about prolonging lamp life. Many things are standard but not what they say about lamp use. A few sites say avoid turning it on and of often (makes sense). A couple sites say don’t ever turn it on and then right back off again, let it stabilize (also makes sense). A few sites say leaving it on for long periods greatly shortens the life and recommend no more than 3-5 hours at a time. However, while shopping over a year ago I remember reading something saying that with modern lamps this was no longer an issue, but I can’t find that again.
If I did use a second PJ as a backup I would only turn each one on and off no more than twice a day and usually only once or even not at all as I would still maintain a small monitor for some mundane computer work.
The biggest hassle I’m running into right now with the backup system I’ve got is where to place the HDTV. There are just no appealing options which means pulling it in and out of the room. That is not such a pain in and of itself but I already ran into a hiccup last week that caused me to waste half an afternoon troubleshooting why my Vista computer stopped seeing my Samsung DLP as a Samsung and only saw it as a generic non-plug and play monitor. And failed to load the drivers allowing it to display 1920x1080. While both my XP machines were having no problems. I finally traced it to a bent pin on the VGA cable which took me forever to track down because my XP machines booted properly off the same cable. So re-making the connections is also a potential issue if I drag the HDTV around.