You don't want to compile code over SMB, even on a fast network. And what happens when you travel with patchy internet access? I use syncthing to a NAS, and the syncthing data being backed up by the NAS along everything else it contains.

Oh interesting I hadn’t considered this. I guess the only trouble would be if I am out with my laptop and I have no internet connection but this seems like a good tradeoff for simplicity

Beware of interactions with git and syncthing. It's fine for straightforward repos where all you do is commit but as soon as you start doing more complicated branching and re-basing you will start to generate lots of `sync-conflict` files. I haven't really found a reliable way around this so I've decided to just manually rsync from my desktop onto my laptop when I want to work remotely (or more recently, SSH into my desktop directly instead and work off that).

I have a ~/git folder which I keep bare git repos in and push to.

That gets synced and it's been trouble free so far.

Apple's Time Machine still backs up your Mac even when you don't have access to the backup target (USB isn't connected, network isn't available). It just stores the backup information on your local storage and then transfers it over to the actual backup target when it's back online. Don't know if there's similar solutions for non-macOS systems though.

https://support.apple.com/en-us/102154

Restic can backup to a local repository and later copy the snapshot to a remote repository.

But if you’re on Linux, it’s better to use ZFS or Btrfs and native filesystem snapshots, since they’re atomic.

Exactly.