I have mine since 1 1/2 years now, and this never became a problem. In the beginning I checked if there was water in there and dried it, but I stopped doing that after a while and they work as good as they always did.
Not really, although I would minimize that as much as possible. If you're wearing outside in the hot sun, try not to wear it the whole time, take breaks and take it off whenever you're not using them.
Have had these for over a year now and the condensation problem for me happens in colder weather (during winter season of workouts) - the only other time it got wet was when I was doin' the wife with them on and for sure it drenched both the Max and my wife.
Wow are you guys really using your APM for exercise?! Seems like a recipe for disaster to me, absolutely no way I'd use mine for that! Even if not the condensation, the band and muffs getting sweaty cannot be a good smell medium term.