If you keep a journal of what you work on and learn each day it reinforces the concepts so you remember better. And you can use it for reference in the future. This is extra important for juniors starting out when everything is new. Taking good notes will accelerate your growth. It helps develop an understanding of the context you're working in faster.
Here's an example: the first time you learn a design pattern you can create a journal entry about that pattern with some psuedocode. Then next time you want to build something using that pattern, you can look at your journal. Even 10 years down the line and 3 companies later.