The other day I was in the process of keeping a book (I had just finished reading it for the first time) in the book shelf when my eyes fell on another book. There was a time when I had read it at least ten times or so. I took it out, caressed it wondering how much thrill and happiness the book gave me every time I read it in the past. The next instant I noticed the wrinkles on the book's spine. It gave the book a 'worn-out' feel. Immediately I glanced at the book I had just finished reading. Its spine looked fine. I sighed.
The more you read a 'book', the more you risk the 'wrinkles' on its spine.