I have a minimum of 3 flash (numbered) drives and rotate updates to them using the old XCOPY in a batch file that sits on my desktop. One double-click and it updates everything that has changed or been added in selected folders and all their subfolders. One flash trades out with the one in the bank box whenever I open it.
I worked hard a looong time ago to get all my 5 1/4" floppies copied to 3 1/2" floppies, and later all of those to CD's. Now I just use the flash drives for current stuff and important history, but have not copied all the CD's to flash. Fortunately I didn't have any of the other exotic storage media.
Almost none of the old stuff will ever be looked at again, but something might turn out to be important. That's just like all other forms of storage. I wonder if Uncle Paden has gotten that call about elevations on 89th street yet (referencing the Unthinkable thread).