Well, there are monitors, and there are monitors...
All monitors will change with age, it's component aging.
From what I've read there are "professional grade" monitors and the consumer monitors. Anything you can buy at a CompUSA or Best Buy is likely a consumer monitor. The "professional grade" monitors are few and far between and don't come cheap.
So the question is is the difference significant enough to affect you? I haven't looked at images on "professional grade" monitors so I can't say. You will have to form your own opinion.
I like NEC and Sony Trinitrons... but whaddo I know.
Elvis has left the building...