After you have bought a book how many of you actually ever re-read the books?

I do not think I have ever been able to re-read a book. Once I remember I stopped reading a self-help book and then went back to it a year later and tried to re-read the beginning and became frustrated with it because it started to coe back to me. I do not think I could re-read a book (especially a fiction book) where I already knew the ending.

How many of you re-read books?