Michelle, that’s good question. As someone who barely has time to read, I have a few rules I follow.
(1) I won’t read a new/recently published book unless someone I respect recommends it to me.
(2) I choose what to read based on current writing/research projects. That ensures that I’m making the most of my time.
(3) I’ve come to terms with the idea that I don’t need to read every book all the way through. It’s okay to skim some books; and sometimes the best part of a book (and perhaps the only part worth reading, given our time) is a single chapter or even the introduction–as is the case with C.S. Lewis’s masterpiece, English Literature in the Sixteenth Century.