I refer to mine constantly. Just one example: I wrote this one a few days ago and I've already referred back to it for four separate projects in the past 48 hours: https://til.simonwillison.net/python/pyproject

I use them for cooking. I refer to this one every time I want to make a Pisco Sour cocktail, for example: https://til.simonwillison.net/cocktails/pisco-sour

I see notes as a way of accumulating micro-skills - things I know how to do, but not well enough to remember off the top of my head.