I'm a 17-year-old high-school student aspiring to be a scientist (either a biologist, physicist or cosmologist), and I watched a video a while ago about How to prepare to be a physicist. He (the guy who made a video is also a physicist) said that scientists usually don't remember/memorize everything they learner, this includes: terms, equations, formulas, etc. and that sometimes scientist resort to using the internet, books, etc. to remember them. So, my question to the scientists and professionals in sciences is, Do scientist (all type of scientist) remember/memorize every single thing they learned inside their heads without recurring to other sources? or they usually/sometimes forget stuff they learned? I seriously need to know, because I'm a little bit paranoid when remembering facts, terms, and equation, I learned in my science classes in the past. For example, I sometimes re-read what is a polar molecule, polar bonds, equation of friction, the mechanics of evolution, how to read chemical formulas, the stoichiometry of chemical formulas, type of chemical reactions, periodicity trends, the nomenclature etc. everytime I forget or I just wanted to review them once again, because I think I need to memorize all those things for the future.