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CD Recording FAQ
4. CD-R media
4.4. Life expectancy
CDR is considered the safest solution for data storage. However, there have been several voices questioning its real life expectancy.
First of all, no one has measured life expectancy for cdr media so far, since the theoretical life expectancy is too long and has not been proven wrong so far. Speculations for theoretical life expectancy are a result of lab-based simulations.
For these speculations to apply in your case, you have to make sure that some conditions regarding handling of cdr media are fulfilled: CDs must be kept within a sensible range of temperature and humidity levels, away from direct sunlight, dust, dirt and chemicals, and always handles with care without touching its flat surfaces (or the reflective surface if the upper one has a good protective coating).
CDR media have a shelf life of 5 years. This means that blank cds should be used within 5 years from their production. This limit should not be considered as an absolute one, but rather as an approximation.
Once cdr media is used, its life expectancy exceeds 50 years. An average speculation is 70 years, while some manufacturers rate their products for even 200 years. Media based on pthalocyanine are considered to have a greater life expectancy than these based on cyanine.
From time to time, there appears some panic regarding cdr media life expectancy. The cd rot panic during the early '90s is a good example. However, such fears have never been anything more than fears and cdr has proved its value as a long term storage solution.
However, some people find that cds written a few years ago are not readable anymore. This may be due to a number of reasons, like the cdr media being of really bad quality, or not handled properly. A most common reason is that the cd was written incorrectly in the first place. Making a binary comparison of the final cd against the original data is always strongly advised and most quality cdr programs provide an option for this useful verification after a cd is recorded.