Jessica's Book Thoughts

How long does it normally take for you to finish and review a book you received in exchange for said review?

I am feeling guilty because things have popped up and I haven't had a chance to really wipe out a couple of books. One I have had for a month, give or take a few days. I want to read the book, I never request a book that I don't have any interest in. I see people post things like ...I knew I wouldn't like the book when I requested it. 1 star. I don't like children's books. Than why request it?