They definitely go bad. I had two Atwood CO detectors in my RV and at about 5 years the LCD screens started to go bad. I think with an older RV especially you cannot be too careful. You never know when some burner or exhaust component will rust through and suddenly you are breathing deadly gases.
My RV is old enough (1990) that it did not come with any propane or CO detectors at all. So I hard-wired a combo CO/Propane detector to the coach battery and located it near the furnace intake near the stove. Then I installed a CO detector near the overhead bunk and another in the back bedroom.
And they work! A couple of weekends ago we were camping and I ran a cable from my TV to the tape deck of the cab stereo so I could play the sound through the RV sound system. I turned on the ignition to the ACC mode, to power up the cab stereo. Unknown to me, the cab fan never is fully off - even in its lowest mode it is still on and sucking in external air. Since the generator was on, that meant it was sucking in exhaust from the genset. I smelled it, of course, and checked the CO detectors, and sure enough, they were registering the CO. Shut off the ignition and the CO levels went back down.
Steve
