Computerworld had an interview with Kurt Gerecke, a storage expert at IBM, and he warns people for the short life span of burned CDs. He claims burnable CDs have a life span of two to five years, depending on the disk quality.
That's quite accurate, many of my old CDs don't read properly anymore.
"Unlike pressed original CDs, burned CDs have a relatively short life span of between two to five years, depending on the quality of the CD," Gerecke said in an interview this week. "There are a few things you can do to extend the life of a burned CD, like keeping the disc in a cool, dark space, but not a whole lot more."
The problem is material degradation. Optical discs commonly used for burning, such as CD-R and CD-RW, have a recording surface consisting of a layer of dye that can be modified by heat to store data. The degradation process can result in the data "shifting" on the surface and thus becoming unreadable to the laser beam.