Okay, the following is a rant. Read at your own risk.
Okay. So. It all started a few years ago, when I'd hear mutterings about the horrible readers who would break the bindings of their books. True, who doesn't love a shelf full of books that look brand new?
But what about those books that you want to read again? What about those books that you want to keep and treasure for many years to come?
Here's the thing: Paperback books are bound with glue. The younger the glue is, the more flexible it is. If you break the binding every ten pages or so, you'll have stretched the glue while it's still flexible. Years later, after you've read it a few times, pages won't fall out so easily. You can open and shut the book, and the glue has already been stretched to accommodate handling.
But as that book ages, the glue becomes more brittle. If you read the book and didn't break the binding, guess what happens? You open the book, and bam! The glue cracks and big chunks of pages fall out. It may start with one page, but next thing you know, a chunk of twenty pages has to be gently filed between the cover. A few more years, and you lose a page here, one there, and then you may as well throw the book away.
Meanwhile, the less pretty, bind-broken book that takes its place is still holding together sturdily, ready to endure a few more reads and many more years.
So for god's sake, just break the binding, already.