Message from C, C++ talks
I've been programming for 10 years and I still constantly need to look up library documentation and sometimes even language syntax. Once I look up something, I do usually remember it until I finish the project that I'm working on, at which point I often forget it again. :P
There are a few snippets of code that I have almost in my muscle memory, but that's because I wrote those same pieces of code so many times, that my brain simply remembered them.
What matters though (in my opinion at least) is to remember what you need, how fast you are able to find it, and to remember where to look for it.