Estimate for CD lifespans was in the 100 year range, but the only way to really put that to the test is to try them in 100 years.
FWIW, I have some CDs that are pushing 40+ years at this point. They work fine, scratches and all.
In my experience, CDRs and other record-able media can’t handle a single summer in a hot car. Mistakes were made. If you have your hands on anything like that, I agree: focus there first for your data hoarding activities.