I pull mine out, clean it with a sanitizing swab, and put it on, check o2 flow and communications, then give it another wipe with the sanitizing swab and stow it. That way I know that if I need it, it's ready to go, o2 is there, the microphone is correctly connected and the hose is not in a snarl. I don't know how many times I've pulled it out and the mic is not connected correctly. In our airplanes the mic plugs into a small panel which is hard to see and hard to reach, consequently the mask mic plug often gets mistakenly plugged into the hand mic jack. Finding a ball of snarled hose is not uncommon. I once found the mask half full of frozen coffee.
I'm not going to say that these things happen all the time, but they're common enough that there's at least some chance that my quick donning mask isn't going to be quite so "quick donning" if I need it to be. So I preflight it.