You don't have to print it out all at once--just a couple of chapters at a time. At least, I try to make sure that I'm encountering a story from a new perspective as I revise, which means a lengthy cooling-down period, printing it out to revise (I've heard the suggestion of even choosing a different font than it was written in), and not reading ahead of where I'm revising. And the second (light) editing pass I make, I read aloud to make sure I don't skip over bits.