I re-read books frequently. But then, I am a fast and voracious reader. I’ve recently been trimming down my library from around 7000 books due to an upcoming move, and there’s a hardcore of about 2000 I’m unwilling to get rid of because they’re either reference materials or old friends I expect to re-read before I die. There are some things (LOTR, much Heinlein, Oz books, Alice in Wonderland…) that I’ve read a dozen times or more.
I do re-read some non-fiction, mainly history. But most of my well-worn books are fiction.