It is a bit of a problem.
Here is what my TBR pile looked like at the beginning of June, just after I had read for 48 straight hours.
If you look closely, you will see that some of the books from June are still not read.
So my question is, how long should you keep a book in your pile before you give up on it, unopened, and pass it on to some reader who might cherish it? It's harder than giving up on a book you are already reading, because at that point you know you don't like it. But any one of the books in my pile could be The One...