I used to have Debian running on one of my Linode VMs, but I so rarely touched the VM after everything was running. Every year or so I would log in to update something or set up something new, but completely forget how everything was configured or how anything worked. It was disturbing knowing so little about the system that I set up.

I’ve since replaced it with a NixOS installation and the “oh no, what is all of this?!” feeling is gone – it’s so easy to peek at my Nix configuration files and know the state of the entire system. All the installed software, all the configuration, all in one spot. I have the configuration version controlled with Fossil and a copy of it locally. If I ever need to rebuild that instance, I can do it and get it back exactly the same way.

I’ll always install NixOS if possible now. It’s a little difficult to learn the language, but it’s great once you get things going.