CD rot is real, but it mostly affected those discs made by PDO in the UK AFAIK. I have only had it happen to me a few times, mostly purchasing OOP discs on eBay or Discogs, and I was able to get a refund from the seller the handful of times it happened. There are many people out there that are unaware of this still, and others that know about it but try to get over on buyers that may not know.
One problem I have had with certain CDs, that is not CD rot but something else, is where a tiny bit of the plastic layer along with the aluminum layer flakes off, causing read errors. I've had it happen to a few discs that were stored in those Case Logic type CD cases/binders and I tend to minimize my use of those as a result. I've also had it happen to CDs that were stored in jewel cases, as well as on used discs I bought. I think temperature and storage conditions can affect this as well. Changes in temperature may not be good for the health of your CDs.
Basically what I am saying here is that CDs can go bad or deteriorate. It won't happen with every disc as there is quite a bit of variability in CD manufacturing quality out there (I have over 4000 CDs). I have discs from the 80s that are perfect and discs that are only a few years old that are starting to deteriorate. It can be hard to tell that something is going wrong until you attempt to rip a CD using a program like EAC that meticulously checks for read errors and spits out a log. Most programs don't do that.
Speaking of changes in temperature, awhile back I had a CD arrive in the mail from across the country and it was completely ruined when I took off the shrinkwrap. Somehow it had been exposed to a sudden temperature change in a warehouse or on the way through the mail and the plastic layer had thousands of tiny cracks of in it. The disc was straight up unreadable. Luckily I was able to get a refund.
