The curious thing I've noticed over time is that in the 90s as a demoscene coder I remembered a very good proportion of the Amiga hardware registers and how they worked, very rarely had to look stuff up. These days I have to look up things that I use fairly regularly. It may be a function of age of course, but I have a sneaky suspicion that reading stuff from paper manuals and the extra effort required to look things up made me remember them better.
Sure, but I still remember that $dff100 was BPLCON0 (at the time I new what each of the 16 bits did without having to look it up). 5 years ago I did a ton of Python programming, but I would need to look up how to do a for loop now.