This hasn’t happened to me yet, but has to my Brother in law - mobile phone being the prime suspect.
It is perhaps more of a concern than ever, as many of us use a GPS device normally, and have the compass for backup. It may not be used for weeks, and then when you need it in poor visibility…
Probably a good idea to check it regularly, as well as keeping it away from magnets etc.
Curiously, I use mine most often to set a return bearing when I arrive on a summit. It is all too easy to go marching off in the wrong direction an hour or two later In this case where I only need a bearing relative to the summit, reverse polarity wouldn’t matter, unless it had reversed during the stay on the summit…
Thanks for the heads up, Gerald.