|Yes. They're all full. All.|
Commonplace books have a long history, dating back to the 15th century Italy when they were known as "zibaldone", or "hodgepodge books." That's a good way of describing them--a commonplace book can hold a little bit of everything, and each is unique to its owner. Many great minds have used them to store their thoughts and information, including John Locke, Mark Twain, Henry David Thoreau, and Ralph Waldo Emerson. For what it's worth, commonplace books also factored into the A Series of Unfortunate Events series by Lemony Snicket, and that deserves as much distinction as anything.
Allow me to outline my incredibly complicated commonplace book indexing system. Every page of my commonplace book gets the topic of that page on the upper corner, and the right page (only, unless it is a top bound spiral notebook) gets a page number.
When the book is full, and I do mean every-single-line full, I go back and fill out an index card with the labels and contents. I tape it to the back cover of the book, and then I grab up the next one to start all over again.
My commonplace book is a comfort. I know I always have a safe place to scribble down a thought or an image so I can save it for later when I'm going to "really" write. If I'm away from home and inspiration calls, I can do a little novel drafting and the index keeps me from losing the pages in the mix. These books also hold my idea stockpile. If I can't find something to write about, I can flip through them and find all kinds of inspiration. When I do find one of those rare free moments to write something down or read something back, I feel more intensely myself than any other time throughout my day. That's a pretty big gift for a tiny little pad of paper.
It might be a notebook to you, but it is more than a place to scribble a grocery list. My commonplace book is like a beating heart tucked into my purse or pocket, and I am better off for having it there.