So after thinking it over I decided to start pulling my older disc players out and giving them a workout. I now think this makes sense.I believe it is electrolytic capacitors that are the problem, again. They age faster when they're never charged. I don't know the details but I'm all ears for anyone that does.
Lithium and indeed other rechargeable batteries also have problems. They slowly self discharge through internal resistance even if not connected to anything. But you don't want to let them go completely flat as that damages the chemistry, in different ways depending on the type of batteries (Lithium, nimh, etc). So anything with a rechargeable backup battery needs to be turned on often enough to keep the battery reasonably charged.
Yesterday it was the BDP-80 first in line, with a burned SACD-R of Brothers In Arms. (Yes, I own a copy of this)
I will rotate my other two older disc players as time allows. Of course my Oppo 103 is always hooked up and ready to go so no worries there. I hope.
Since I recently copied all my music archive HDD's with a duplicator, they've all had their "workout". Still not sure why HDD's are susceptible to "going bad" sitting around but hey! Ya never know.
My wife's printer, what few times she uses it (hardly ever) always requires me to do something to jog it along, clean the print tray or such. ...and here I've always been telling her to use it or lose it. Decided to take mine (and other's) advice and do the same with all the electronics.
So what has this to do with stereo? As was said, always have two working copies. (Life's the same, except for the shoes)