8 episodes.
If the story doesn't turn, if it doesn't get me hooked, if I like sleep more than watching it (I instantly pull an all-nighter if it does), if I put off watching it to do chores all day, I drop it. This rarely happens. I usually try to finish stuff that I started (I just feel it should be that way--if you started it, finish it) but lately I don't feel obliged to torture myself into completing dramas that I think are going nowhere.