Programming isn't about memorization, it's about learning a skill. I use so many programming languages and APIs that I can never remember all of the exact syntax. I keep cheat sheets handy and I use Google a lot. But, here's the key: I'm only looking up quick details to remind myself. The important concepts I know deeply because I've been practicing for years. You need to learn the concept of a for loop. If you forget the exact syntax that's no big deal, you can look that up in 10 seconds. But if you don't know when to use a for loop and when to use a while loop, that's going to slow you down a lot. now you might ask What about concepts, design patterns, SOLID etc? They're important but hard to remember so how do you learn them? And the OP too mentioned CS not programming. Design patterns are tools to help you write very large programs with lots of people. It's very difficult to learn design patterns if you've never written a large program before, it's hard to understand the need. Imagine trying to explain advanced strategy to someone who's still learning the rules of a game like chess or basketball. They won't understand any of it. You have to play a lot and get to know the rules of the game inside out before you can learn strategy. Both OOP and design patterns are like that. They're not the rules of the game, they're strategies to help you succeed in writing larger programs. And just like all strategies, they're just guidelines. There are times to ignore them. The best players sometimes make up their own.