I don't count my rereading, but for good books, once is never enough. When I got the the end of "Satanic Verses" for the first time, I was so taken, I started it again the very next day. Similar with "Against the Day". If I had to guess, the most rereads I've done is ~20-30 rereads of "Cats Cradle". Part of the reason for that is it is such an easy read, and I can usually finish it in a day or two. Its also a great novel. I'd like to say I've read "Gravity's Rainbow" that many times, but for its density, having read it four or five times is a feat unto itself.