I have around 300 CDs. They are stored indoors, in sleeves, not in the car. Truthfully, I don’t listen to them very often any longer. But I do have a few that have deteriorated. When I’ve played them, they sound sort of like an album with something sticky on them. Like a "fuzzy" sound in the playback. It’s a few... less than ten... but it’s still there, for sure. Someone above commented that you can just rip them onto a new CD/R, but that doesn’t work. It just records the "fuzzy" sound.
So, I think that like anything else, they aren’t truly a "forever" medium.
So, I think that like anything else, they aren’t truly a "forever" medium.