For non-fiction, I give everything a 15 minute skim to get the Very Big Points. Only then do I decide on if the details are worth chasing. (Usually it's if I need more convincing, or explaining) In many cases (example: Gladwell) 15 minutes is enough, and you can get through 15-20 High Concept books in the time that this author suggests that you read one.

This is a big change for me - I used to give every author the benefit of the doubt, and drove to finish everything I picked up. Then I ran out of time.