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.
Other than my password manager database, the rest of my backups are not overly valuable. I don’t really need my 2016 factorio saves, but I have them. Adding more things to backup is minimal effort so I do, but if the space taken up becomes a concern there is plenty I could trim from it.