Call me paranoid, but I have three. On one, I save the game every time. On the other two, I alternate saving. The reason for this is so that if somehow the game saves two corrupt files, I still have one left over that I know is uncorrupted. Also, I never have two cards in at the same time for the fear the a power surge will wipe both out. I also switch between memory slots in case one of those is damaged as well. And finally, I only put the cards in and take them out while the power is on. Even still, this isn't flawless. If I saved a corrupt file onto the alternating card, didn't check it, and then saved a corrupt file onto the every-time card and the other alternating card, I would have all three corrupted. The only way to avoid this would be to load the game from each card I last saved it on when I start and make sure each works. Slightly paranoid? Maybe.