My father told me he wanted to make USB flash drives of all the scanned and digitized family photos and other assorted letters and mementos. He planned to distribute them to all family members hoping that at least one set would survive. When I explained that they ought to be recipes to new media every N number of years or risk deteriorating or becoming unreadable (like a floppy disk when you have no floppy drive), he was genuinely shocked. He lost interest in the project that he’d thought was so bullet proof.
Do optical disks degrade if protected from the elements? A stack of Blu-ray disks could store quite a bit.
The commonly used optical disk technologies degrade over time. CD-RW more rapidly than CDR. It’s even worse for higher-density media.
Depends on the disk technologies.
CDs are prone to flaking, otherwise most disk are suspectible of oxidation (disk rot) if stored improperly. M-Disk is a long-life variant of both DVDs and Blu-Rays, although more expensive. However, write-once disks are very ransomware-resilient, and I recommend to add a write-once media to any proper backup setup.