Lately I’ve been reviewing my highlights from non-fiction Kindle books I read years ago.
I can often review a whole book in 15 minutes and find something that feels fresh and useful today. (Assuming past-Josh noticed some interesting stuff. He wasn’t always the brightest bulb in the box.)
So not only are highlights a good tool for focusing as you read and reviewing when you’re done; they can make a very good precis for future-you when you’ve inevitably forgotten half of what you hoped to absorb from a text.