I use a single text file, have done this for decades. I dump everything into it and don't worry too much about structure, it's an incredible resource for "remembering" minutia, things like "what was that server that i thought might have had some issues last August?" Just a quick control-S and I'm there. My current 7+ year old notes file has about 100K lines in it right now. I can tell you what I was doing last year,…
That sounds quite elegant, but seems this is only possible if you work out of a single machine almost always. Perhaps it could be made into a service? As long as explicit effort is taken that there's absolute minimum extra effort as possible!
I've gotten to the point that anything important enough to keep around I basically just put in a git repo somewhere.