I rarely re-read anything as I just feel there are far too many books I've never read that I won't get to before I do. But there are a few children's books that are an exception. I have read The 101 Dalmations by Dodie Smith probably about 20-30 times or so, maybe even more. Rascal by Sterling North, at least 10 times, probably more.
I haven't read any of them in years though. The last time I read 101 Dalmations was around the time that the live action Disney movie with Glenn Close was released. It made me nostalgic, so I bought another copy of the book and read it. It is still in my library.
Oh, wait, there is one adult book I've read more than once -- Memories by Mike McQuay. It's a a very interesting time travel SF novel, which is sadly out of print. It's the only book I've bought twice on purpose
