I'll probably keep some of the how-tos and syntax reminders for various tools -- looking at you, ffmpeg and defaults -- but most of it, even many of the curated notes from books, is just junk that I carry now carry around, with the added bonus of that little voice saying "hey, you haven't reviewed me in a while, maybe you should because _this time_ there'll be some productivity hack or life-changing insight you'll glean from it".
When I look at the physical hoarding tendencies of some people close to me, it looks scarily similar.
A long time ago someone told me that you should always be wary of the difference between what you know and what you can look up. Trying to merge those things seems to have been a mistake for me.