In general, friction is bad for box corners, I think a lot of collectors store theirs in loose zip-strip baggies or special thin plastic shell boxes. The boxes are the best bet, since they're rigid and help to avoid another problem, impact damage. Even a slight impact from a thumb in the wrong place can cause a little warp, nick, fold or permanent bend. These things are actually more vulnerable than baseball cards in some ways because they have volume to them.

Other things to be aware of: direct light, dust, small children, and nuclear fallout.

Haha, yes they're stored away from children but yes they are still in bubblewrap shipping bags. But do you happen to know of anyways I could get ahold of these NES hard box cases? I think I've looked on ebay awhile back and had no luck. I've seen many collectors have them but have no idea how. Any info will help.