When Should One Quit Reading THAT Book?

So, earlier this week, I started listening to an audiobook that I have heard very positive things over - Apple Tree Yard by Louise Doughty. Yesterday, after listening to under 3 hours of this audiobook (3 hours out of around 13 hours), I had to stop listening to it. I COULDN'T BEAR IT ANY MORE!!! I disliked the writing style, have serious hatred for the characters and, for a reason I don't understand, I didn't warm to the narrator.

And because of this decision, I began thinking about all the books/eBooks/audiobooks I have stop reading within a few chapters within 2014. And I have counted 1 true book which I have stopped reading because of hatred: Apple Tree Yard for the reasons I stated above (oh, believe me, I could easily go on a rant about that - just ask my other half). For the books I started but I wasn't in the right frame of mind to read, I have counted 3/4 (Frostbite by Richelle Mead, The Dead Girls' Dance by Rachel Caine and Witches of East End by Melissa de la Cruz from the top of my head [as I can't remember the fourth]) and there was one I nearly gave up on but Twitter ordered me to keep going (thanks for that, Twitter. Throne of Glass was ok once it got going. Let's hope Crown of Midnight is better than the first, like everyone seems to be saying...)

But that got me thinking: how long do you stick with a book before you stop reading it? Do you struggle on with a book even though you seriously hate/dislike it? Do you give yourself a page mark - say page 100? - before you decide to keep going or stop? Or do you do what literary agents do which is read the first 3 chapters and take it from there?

And what do you do with eBooks? Do you give it a certain percentage (20%? 25%? 15%?)? And then what do you do? Do you create a folder for those unfinished stories?

Leave what you do with books as I am really intrigued over what everyone does...