I've a Vutec 1.5 gain wall screen in used for 3 years. It is there on my bedroom all the time in the 3 years. From time to time I clear off small dust using a hand blower. The projected image still looks perfectly fine to me. The projector is a NEC XG85.
But I just keep thinking maybe, just maybe the screen should start to lose some brightness/gain for all these years hanging there exposed to open air. To my eyes the screen still looks pretty WHITE (without the projector), but I can't remember if the screen looked WHITER when it was arrived new! The projected image of course looks fine because after all I calibrated the projector according to the screen! If the screen is starting to turn yellowish and losing brightness, that means I'm actually pushing the projector to compensate.
How do I know if it's time to replace the screen? Thanks in advance.