Yeah good ones allegedly last 200 years if stored correctly. Cheap ones are 5-10. 20 can be expected for quality CDs stored correctly.
But no matter the claimed quality, it’s a gamble. Our local library had a lot of 10-20 year old CDs that had developed microbubbles.
5 years is low range for CDs, but common enough that you should be taking backups for anything you keep longer.
Don’t conflate a mastered CD with an aluminum data layer with a recordable CD-R or CD-RW, which use organic dyes that have a significantly shorter lifespan.
A properly manufactured CD can last 200+ years if it’s stored in a dry environment free of UV exposure and high levels of moisture.
Even a quality CD-R can’t really be expected to retain all of its data integrity for much more than 10 years.
First released in Japan in October 1982, the CD was the second optical disc technology to be invented (–Wikipedia)
Sorta doubting whatever study found proof that a CD can last 200 years…