Recently I was in a position where I had to look for a job after 7 years. Initially it was a bit difficult as I had forgotten much of the basics, despite using them often.
During the interviews I wrote down all topics I struggled with or didn't understand fully. This helped me study, better prepare and eventually find a job.
Now I decided to put that knowledge in Latex so that I can come back to it and revise or even deepen my knowledge now.