Properly stored is the key. Most people use the cheapest storage media available, store them somewhere inappropriate (like the attic or crawl space ) and do not have enough backups. Things are improving, but that does not help the stuff from 1980 to now that are slowly demagnetizing, oxidizing and depolymerizing, and live on floppy discs that the labels fell off of.
(Sorry for OT again...)
Perhaps it is time for me to convert that stack of IBM 360 computer cards I have stored in the attic.... oh and that cigar box of paper tape. (I really still have such things)