I typically see it through, and it usually works out. I did abandon Blood Meridian a few years ago, and I felt bad because I had really liked the previous McCarthy books I had read.
As I get older, I am more apt to stop reading a book that I don't like regardless of where I am. That said, I always feel a bit guilty when I do. I guess it's that voice from the old man saying, "always finish what you started".
What are your opinions on this? Do you bail at the first sign of trouble or do you see your commitment through?