Right now I’m creating a nightly restic snapshot of my server on borgbase and on some spare drives, and keeping the snapshots forever. There’s a ton of daily churn in my data though, between databases and logs and other files that don’t constitute ‘real data’ but might be needed to restore the app.
Yes, I have that exernal HDD lying around somewhere near the PC, and it was at least 4 or 5 times that I backed up a lot of files on it.
I think I keep it for more than 10 years now.