Confirmed: It’s not just an urban myth (as I’ve seen some people claim) that burned CDs and DVDs deteriorate after less than a decade.
This weekend, I tried to read several hundred files from a DVD I burned seven years ago. Approximately 20% of them were corrupt to various levels. Some were totally unreadable, and some were readable but partially corrupt.
These DVDs were not stored in the sun or in the heat. They’ve never been wet and they have no scratches; the media just deteriorates after a while.
If you have any DVD or CD older than 2-3 years on which you have vital files, it’d probably be a good idea to get those files to other media ASAP.