Are Classics Re-readable?

As part of my “Top 25 Series To Read In 2013” reading challenge, I’ve read a fair amount of books this year that can be considered to be classics of science fiction and fantasy, in all their different forms. There is a certain charm to all these novels that has persisted long after they were first published. Whether we talk about Frank Herbert’s space operatic political intrigue epic Dune or Margaret Weis and Tracy Hickman’s true-to-style epic fantasy Dragons of Autumn Twilight, I’ve had a lot of fun with these novels.

And that is my question: are they re-readable? I’ve read Dune and Dragons of Autumn Twilight several times since when I first read them in 2001. I think they are rereadable, but I’m not completely sure. Is the question answerable in part with regard to whether the book is good or not? We shall see.