I have learned many of these things at some point. Unfortunately, I have also forgotten most of it. Some of it I still remember to some degree, or just the basic idea, and can probably reconstruct it given some time, or easily look it up and remember. However, many of the things I have completely forgotten, and it would take more time to understand it again. I am not sure I can keep so many things active in my memory…
When I wrote this list I certainly wasn't expecting/recommending all of this to stay in the reader's head forever.
Rather: if you've worked with something deeply at one time, then -- even if you've forgotten the details -- you still can pattern-match on it later. And then look up whatever you've forgotten!