I have all of mine on cd's, labeled in categories.
All USB flash drives will eventually go bad because their internal memory chips can only be used a finite number of times. ... Since every other component on USB flash drives can be prone to failure, another vital part of the device is likely to fail long before the memory fails from overuse. Most people agree their lifespan is 10 years or so...
lifespan of CD (read-only, such as an audio CD) 50 to 100 years,CD-RW (erasable CD) 20 to 50 years