What Makes a Book Worth Rereading?

What is the thing that makes a book worth rereading? Today the question may as well be, what makes a screen worth returning to? Or more dramatically, what makes a religion worth following in each new day of one's life? This question was posed to me the other day and when I sat down to write today, it became the topic of my writing. When I return to words with capital letters like "Intelligence", "Beauty", "Quality", I often find them empty or overflowing with meaning. The God or Gods I know live not in these words but in my experience of the books I reread. My capacity to experience, and to "taste" from my experience, is far deeper than my ability to channel that experience to you, dear reader. The best answer may be "I only know it when I see it". Laozi famously said that "the Tao that can be spoken is not the eternal Tao". There are no words for the eternal Tao because it cannot be compressed into any description, any attempt to codify it would fail to capture its capacity to grow outside of the boundary of that description. It is a continuous unfolding process which is already humbly interpreted by our senses, perceptions, and memory. And yet some of our reflections endure to the extent that they are worth rereading. How can that be?