In Fall 2025, I started writing notes for the subjects I've learned. I am generally against typing notes, as they're an inefficient way to learn, but I think once you know a subject, typing up notes for future reference can be very beneficial.
I develop the subjects in a way I see logically fit, and as such I do not follow the approach of any resource I know. I am more mathematically precise than most resources, try to always develop things as simply as possible, and I have certain computational results that are hard to find elsewhere (e.g. vector spherical harmonics for approximating the vector potential). I will also sometimes skip something if I think I can derive it myself later or if I know I won't forget it.
My notes are not meant to be learned from, but if you already know the subject they cover you might learn something from reading them.