As some of you may have noticed with my round-ups, I love to re-read books. I'll frequently re-read an entire series in order to prepare for a new book in that series, partially to remind myself of what happened before and partially to remember why I care about these characters and worlds. Some, I just re-read because it's comforting - sometimes, it's helpful to take a step back and go with what you know for a little bit.
A co-worker once asked why I bothered to re-read books. "It's not like you don't know what happened!" Well, yes and no. I freely admit that my memory for details isn't fantastic - I can usually remember broad strokes, but not the nuances of the book. The nuance is what makes the whole experience of reading enjoyable.
Re-reading also lets me focus on something different each time. My husband mentioned this with some of the mysteries he's currently re-reading. He remembers who did the crime, and now he's reading the book to see what clues the author leaves for the reader about the ultimate resolution. It's a fantastic exercise in seeing how a good author works (or learning how a not-great author doesn't work as well - some books simply don't hold up to a re-read).
Reading in general is such a bizarre concept if you think about it. You, the reader, are taking the words written by an author, during a specific time in their lives, and absorbing them in a specific time in your life. That time of life will color how you interpret those words. Reading a book in which a character grieves a loss when you haven't personally felt that kind of grief is a very different experience than reading it after you've encountered that grief is. As you change, so does your perception of the books you read. It doesn't always change for the better - there are certainly some books that I devoured as a child that I couldn't get through a single chapter of as an adult. Regardless, taking a look at something you read months or years ago automatically resets your expectations, even if you do remember the plot and the characters. It's always different, even though the words remain the same.