Randy Murray gives some sound advice on backing up your digital stuff:

Last year I needed to use a play that I wrote nearly thirty years ago. It was originally in a digital form, but that format, a Lanier word processor on huge floppy disks, was long inaccessible. But because I had it on paper, it was no problem to read and use. I’ve updated it to a new digital edition (I retyped it and rewrote it), but I’m keeping copies of each edition on paper. I also keep really important digital files in as raw a format as possible. For example, save as text, not a proprietary word processor.

I don’t do enough of this and I should. And you should too.