As of Saturday, I've been going through some old notebooks from the garage. I used to be a notebook junkie, back in my youth. Why? Because I was always writing something. Whether it was fiction, a journal, notes, etc. I've always been a note junkie, too. Unfortunately, before the cloud age, this meant a lot of notebooks and being afraid to throw away any of them in case there was something in there that didn't eventually get realized somewhere else.
I'm mostly throwing away the stuff I'm going through, but there is an occasional gem here and there. These notebooks date between high school and college days. Any fiction I was writing at that age is pretty bad, but sometimes an idea was good. I try to keep ideas with potential, but stuff that's just bad I toss. And then there's the notes upon notes upon notes. You never know what you'll find in a notebook of mine. There could be like ten pages of Algebra II notes followed by a short scene for stage, and then notes on a two act play. Good gravy.
I mostly went digital several years back and have made little use of notebooks since then. While a lot could be said about the fragility and non-ownership of digital, a lot could also be said about notebooks sitting in cardboard boxes in your garage for years and fragility. Those notebooks easily could have been chewed up and dumped on by mice or whatever. Or flooding in the basement of our previous place could have destroyed them.
The key to me when it comes to your work, notes, etc. is that you have multiple copies. Period. Some people put all their eggs in Google Drive, or Microsoft OneDrive, or Dropbox, or Box, or Evernote, or OneNote, or whatever other digital platforms/clouds. But I try to make multiple copies in several of these places. I may draft in one place, but then edit in another, or simply copy stuff over to another place at some point just to make sure I have a backup.
Backup, backup, backup. That's what you want to do.
Never underestimate backing up. Because at some point a service you use everyday will shutdown, or the cloud will hiccup and dump your stuff or whatever. Backup, backup, backup. Always backup.