If you look at a history of my book reviews you'll notice that I've never rated a book less than a three. There are reasons for that and of course here they are in list form:
1. I like buying books. And just like with any other purchase, I'm very careful about selecting the best. My progression of analysis for book buying (don't I sound intelligent?) is to look at the cover, then read the blurb, and then if I don't know the author I'll read some of the free excerpt. This saves me from choosing books which I'll regret having spent time reading. It's like I'm a book buying genius. I went through a couple of month last year where I read all 5's. Best months ever!
2. I rarely have people send me their books. I'd rather buy them myself so that if I don't feel like reading it or if I start it and don't like it, then I don't owe anyone anything (not that I do anyway, though). I have exceptions to this rule. There are some authors who can send me their books and I'll gobble it down within the next couple of weeks. This throws my TBR list all out of sync.
3. If I rate a book a three I'll contact the author and let them read my review. If they want me to post it then I will. A three is not a bad review, it means I liked it, so most of them tell me to go ahead. Some authors ask me what I found wrong with the book and I let them know. These are the kind of authors I like best, always learning.
4. I hate wasting time. If a book isn't good. Then I won't spend my brain power writing a review about it and then posting it. I have too many other books to read.
What's your book review policy?