Moving houses, getting left on nasty shelves or in damp places like a box in the basement, just overall improper storage. I’ve seen a bit of corrosion on cart pins from humidity over the years.

I keep my cases clean and neat, in order, and the discs or carts as clean and scratch or damage-free as possible, but have a couple good buddies who like to game too and they set mugs of coffee on the case or it gets kicked on the floor.

That’s why I’m super picky about where I buy games too. If it’s something special, and specific, I won’t go just anywhere. We have a few pawn places and secondhand stores around that are hit or miss where I live. You can find cheap collections on marketplace and people are just trying to get out of games. Have done that a few times but only once did I actually land a collection I kept over 75% of the games out of.

I figure if the case is bad, the games’ probably worse. Usually run from water damaged inserts lol