According to manufacturers' data sheets and other technical literature, thirty years appears to be the upper limit for magnetic tape products, including video and audio tapes. LE values for storage media, however, are similar to miles per gallon ratings for automobiles. Your actual mileage may vary. Recently, articles have been appearing which suggest that the life expectancy of magnetic media is much shorter than originally thought. Because of the confusion that can result from such a statement, NML officially responded with a letter to the editor that appeared in the June 1995 issue of Scientific American.
Some people assess storage media solely in terms of media cost.
This view assumes that the sound, images, or information stored on the media have no intrinsic value. However, a storage medium should be evaluated in terms of the cost of losing the recorded information in the event that the storage medium degrades irreversibly. The value of the tape cassette must be equated with the cost of preserving the data. It may also warrant the cost of making and keeping replicated copies of original data and stockpiling systems to play back the data at future times. When purchasing media of a specific format, some archivists are required to deal with a procurement bidding process.