I've never read a book more than once, not even a comic book when I was a kid. I have, though, seen cerebral films (pretty much my favorite kind) as many as 5-15 times each.
What I haven't seen anyone mention here in the comments, is reading several books on the same subject, but from different perspectives. IE, 2-3 history books, by different authors, on the same country and era. This is something I have done and do get a bit of enjoyment out of.
I really enjoyed taking that approach to the Vietnam war. It was edifying to read a general who was there describe the exact same events as a journalist writing post-9/11, yet only the location and time matched up. It made their biases stand out so starkly.
What I haven't seen anyone mention here in the comments, is reading several books on the same subject, but from different perspectives. IE, 2-3 history books, by different authors, on the same country and era. This is something I have done and do get a bit of enjoyment out of.