I don't know about the truth of it but they say most storage media has a shelf life--if you believe that then you may want to consider something designed for archival, m-disc springs to mind which some claim has a life span of 1000 years from memory but they are a fair bit more pricey and would probably only be worth it for the important stuff.
EDIT: The concerns about the lifespan being short may be overblown though. I just wouldn't risk it for genuinely important stuff.
I don't know about the truth of it but they say most storage media has a shelf life--if you believe that then you may want to consider something designed for archival, m-disc springs to mind which some claim has a life span of 1000 years from memory but they are a fair bit more pricey and would probably only be worth it for the important stuff.
EDIT: The concerns about the lifespan being short may be overblown though. I just wouldn't risk it for genuinely important stuff.