#1: I've read previous books in the series/previous works by the author.
If it's a series I enjoy, of course I'll buy the newest releases. Also, if it's an author whose works I've enjoyed enough to know I'll like whatever he/she writes in the future, I'll buy those books too before reading them.
Think Cress and The Nightmare Dilemma.
#2: I've read an ARC of the book.
If I read a book for review and really enjoyed it, of course I want a physical copy. Now, this doesn't always mean I'll buy the book immediately after its release (case in point, it took me eight months to acquire Being Sloane Jacobs), but it does mean I want it for my shelf.
I could also include "I borrowed the book from the library and liked it enough to buy it" under this reason.
Think On the Fence, The Kiss of Deception, and Wish You Were Italian.
#3: The book has come highly recommended, and trusted bloggers have given it good reviews.
I rarely buy a book I haven't already given a test run (whether e-galley, library, or one of the reasons from #1). So for me to buy it before reading it, it has to have good reviews from friends and it has to come highly recommended.
Think The Falconer and Magnolia.
#4: I'm feeling especially daring.
There are some books I'm dying to read, and I never got an ARC, or I haven't seen a lot of reviews, or my library would takes ages to get it in. So I'll go ahead and buy the book and hope for the best. If worse comes to worst, I can always sell it or offer it for trade. Thankfully, most of my recent risks have paid off.
Think My Faire Lady, Wildflower, and Illusive.
So why do *you* buy a book? Is it for one of the reasons above, or do you have an entirely different one? Let's talk!