100% to both. I have a hoard of PDFs. I use Dash as an offline doc browser. I save interesting links in a bookmark app and I still can find libraries documentat

100% to both. I have a hoard of PDFs. I use Dash as an offline doc browser. I save interesting links in a bookmark app and I still can find libraries documentation and source codes on web search (duckduckgo). So I just freshen up as I go (or on my free time). Memorize what I need/like and capture what I found interesting. I was doing Advent of Code in Common Lisp and the loop keyword page was always open (It's a mini language on its own). Later challenges became easier, as I learned new ways to iteratively express the solution. I could be faster with generated code, but having a bird view of the map will lead you to more interesting routes (more often speed is not the issue, correctness and maintainability is)