I read an article in a trade magazine recently regarding the longevity of CD and DVD. Here are some of the recommendations it listed.
CD and DVD Storage Recommendations
Do you know how to properly store their CDs and DVDs? Do you? Following these simple tips can help prolong the life of data burned to these disks.• Start with high quality media. Fuji CD-R for Photo, Kodak preservation cd/dvd or Delkin Archival Gold are 3 examples.
• When burning a disk, always let the CD or DVD burner verify that the data has been written to disk successfully. The extra few minutes at the time you burn the files will ease a lot of heartache when you try to access files on a disk that had a problem during the writing process, and wasn’t verified.
• Store disks vertically.
• Store disks in a protective case.
• Don’t use labels or tape on the media.
• Don’t write on the media, even with markers that say they’re safe for the purpose. Instead identify disks by writing on the center hub area, and using the paper insert that comes in a jewel case for fully listing what is on each disk.
• Disks should be stored at low temperature, low humidity, and in low light.
• Migrate to new technologies as they emerge.
• Keep redundant archives of important files.
Here is another article of interest.