For context I have been writing professional code since the early 90's, and while I have a ton of experience, I still will pull out the manual or google to refr

For context I have been writing professional code since the early 90's, and while I have a ton of experience, I still will pull out the manual or google to refresh myself. The difference between being in college and the professional world is it is expected that you have to use reference material to do your job effectively. And over time things you use frequently or have solved frequently will stick in your head. The things you have solved, but not used regularly will require more time to refresh. The more you specialize in solving a specific type of problem or in a specific area of software the less referring you do for everyday problems but it will still be a part of your normal day. Also, when you read something, the only way to truly understand it (and tradeoffs) in my opinion is to write tests and actually test it. That is something that is super critical to success, doing small test projects to prove it out and see what works and what doesn't. Because frankly what is written in the manual and what it actually does or how you actually do it might differ still.