But, it makes things easy. I have e.g. a home computer, a server in the closet thing, a laptop and a work computer all with a shared Syncthing folder.

So to bolster that other thing, I just have a simple bash script that reminds me every 7 days to make a copy of that folder somewhere else on that machine. It's not precise because I often don't know what machine I will be using, but that creates a natural staggering that I figure should be sufficient of something goes weird and lose something; like I'm likely to have an old copy somewhere?