The first thing that will cause me to put down a book is to find it isn't what I thought it was or looking for. That will usually happen within the first couple of chapters.
From there I'll set it aside when it no longer is a pleasant read, which can be caused by:
- The amount of editing errors.
- Wandering off topic enough that you lose the pace of the read or storyline.
- To many sentence structure issues, so that it's difficult to understand what is meant and you have reread sentences repeatedly.
- Piles of adjectives and adverbs that destroy the pace of the story.
- When the writing is very mechanical, so there is no sense of the story or characters.
- When the story is inconsistent or becomes unbelievable.
- When the story is factually incorrect and poorly researched.