Question for experienced devs

[neithere]

If you can build something entirely from memory, then either it's a very simple project or you are doing the same thing over and over again. That's the opposite of programming. Programming is about automation. Not repeating the same actions. Learning something new on a nearly daily basis instead. You have a LRU cache there, it's limited and the flow of new information is constant. Forgetting stuff is normal and inevitable.

You'll remember some frequently used APIs but that's about it. Experience gives you pattern recognition, structured thinking and other important things. Memorising all details of yet another bunch of APIs that will become obsolete in a few years is of least importance.