Patrick Rhone reminds us that our notes are always there for us.

I have found that the longer my used notebooks sit on a shelf, the more valuable they become to me. That I often do not — can not — recognize the full worth of a thought, idea, or conversation I have captured until it has gone long forgotten on a shelf or in past pages. Only when I stumble upon it with eyes anew does the true importance shine through.

— The Shelf of Notes by Patrick Rhone

Make sure you review them at some point. They can make great reading.