As someone already mentioned, a lot of it has to do with the way the media is stored.
Just for kicks, I tried some old 5 1/4" floppies (from my C= machines) a few years back. (Some of them nearing 25 years old... YIKES.) Everything was fine. My Amiga floppies are also OK, AFAIK.
Everything is stored in disk containers, and FWIW I live in a dry, temperate climate.
Obviously, they will eventually be unusable, my *guess* is sometime during the next 10 years. I may archive a few things, if I find time someday.
