I just set up everything via ansible and comment everything religiously, I’ve gotten to the point where I have playbooks for my laptop and desktop so if I have do do a clean install I just have to run the playbook and everything is set up and installed to my liking

It’s annoying to go to my playbook to make changes and rerun it every time I want to install or remove anything from my daily PCs, but it pays off when I migrate computers or for some reason have to do a clean install

And for high level stuff and things not in ansible I keep a tiddlywiki since no matter how catastrophic the failure of my systems I can always find a way to access an HTML file for my own reference