Actually this problem has been solved in jaspers, You don't be worried about this problem if you obey some basic rules.
Keep your console in a cool place, not in front of cooler, (direct wind).
Also don't turn it off/on too much. that hurts console more than playing several hours.
Up to Valhalla, the newer the revision, the longer the board would last before it RRoD'ed.
Can't comment on Valhalla since they're only in the new slims and they haven't been out long enough to come up with an average.
Supposedly better cooling means little to no more RRoD (now Green Light of Death), but the much smaller case can't be good for heat movement. We'll see.
i concur. this problem occurred mostly with the initial batch of 360s and usually when u kept the 360 in a well ventilated space with proper air circulation it didn't heat all that much. but with the later editions most problems were rectified. to be safe..as dartkone points out..take a break after say 2 or 3 hours of play.
you should be able rondos that. I believe there is a setting (I don't remember exactly where so you'll have to do sole searching, I think it's somewhere on console settings) that makes it turn off automatically after a certain period of time. I believe it is either three or six hours, so I think it's most likely that that is where your problem is. simply turn the setting off.