Linux

When I researched this previously I concluded that there are two very good options for regular backups: Borg and Restic. These are especially efficient at backing up a diff of what has changed since the last backup. So you get snapshots of your filesystem state at each backup point without using a huge amount of space. You can mount any snapshot as a virtual directory. After the initial backup, incremental backups take a minute or two.

I use Borg, and I back up to cloud storage on Borgbase. I use Vorta as a GUI for Borg. I have Vorta start automatically when I start my window manager, and I have it set up for daily backups. I set up the same thing on my kid's computer.

I back up my home directory. I have some excluded directories like ~/.cache, and Steam's data directory. I use Baobab to find large directories that I don't want backed up.

I use the "exclude caches" option in the Borg "create archive" settings. That automatically excludes Rust target/ directories because they follow the Cache Directory Tagging Specification. Not all programming languages' tooling follows that spec so I also use directory name pattern excludes. For example I have an exclude pattern for .*/node_modules/.*

I use NixOS, and I keep my system config in a git repo so I don't need backups for anything outside my home directory.