Whenever I find myself learning about something where I know that I will not use it frequently enough to actually remember its keystrokes/commands/etc. I create a new “personal documentation” for it as an .org file (I have a central folder and a git repo for all of them). Here I’ll write all the information (like keybindings, details of commands, common procedures, concepts, etc.) down that is specific to my own use-cases and organize it in a way that makes sense to me.

It takes some time and effort and may seem redundant when there is good documentation out there already (as with most of Emacs). But still I find myself wasting a lot of time looking for that one piece of information in the docs where I forgot how to even search for it. Maybe it works so well for me because I kind-of enjoy the process of writing it (which many people might not). But I feel much less frustrated afterwards when I come back to some tool or language after years of not using it and find it really easy to remember what was important to me at the time and how to do X.

Tools like Casual Calc are great because they reduce the need to do that manual work of going through the docs and writing down what one want to remember in a (for them) more clear/concise/practical way. However, the way they select and organize knowledge/commands only reflect the common use cases, so there may still be a need to write stuff down.

As a more general helper, I really like to use Emacs Calc with `which-key`, which provides a similar interface to see what keybindings are available under a specific prefix-key. What also helps is if you press `h` and then search for a specific function (`h f`), key (`h k`), etc. or just type `x` to enter a function name directly (or by keyword using text-completion).