Reading a book isn't much of time investment, either, depending on how quickly you read. I read most novels in just a few evenings (sometimes just a single evening if I'm really into it), and then I'm out of books I'm interested in reading for a while. Even though I re-read all the books that I like multiple times, I still have more reading time than reading material.

When I'm out of books I want to read (which is most of the time), I just switch to some other activity — like watching YouTube or reading my phone — in the hour or two before bed. But these are a lot more disruptive to my sleep than books are.

If I had a policy of never re-reading books, this situation would be a lot worse.