So I know this is the opposite of what OP is asking, but I've taken the stance recently that I won't re-read another book. There are books that I would like to re-read, but they come at the opportunity cost of reading others.

A fellow traveler in a Guatemalan hostel broke it down to me like this: - let's say as an avid reader, you're able to read 12 books a year. - let's say you have 50 years of reading left in you, that means you have 600 books left to read in your lifetime

That back-of-the-napkin-math put things into perspective for me. So many great books to read, so little time. It's also for that reason that I have no qualms about putting a book down that I'm not into.