I reread books rarely but I've identified the conditions under which I do it: when I remember a book strongly but can't remember why, when I've changed enough that I expect to read it differently, when someone I care about is reading it for the first time and I want to have a current relationship with the text.

The most productive rereads are the ones where I was wrong about the book the first time — not wrong that I liked it, but wrong about what it was doing. The first time I read Never Let Me Go I read it as a science fiction novel about clones. The second time I read it as a novel about how people choose not to know the things that would require them to act differently.

The book didn't change. My ability to read it did.