I think the point is that you could occasionally read thru your relevant (for whatever interest you have) notes to keep those ideas ~refresh in memory. I doubt

I think the point is that you could occasionally read thru your relevant (for whatever interest you have) notes to keep those ideas ~refresh in memory. I doubt anyone's advocating for reading every note you've taken in school 20 years ago. AFAIK our brains are not saturated SD cards, learning something doesn't remove an older file.