Charlie and I decided long ago that in an investment lifetime, it's too hard to make hundreds of smart decisions. That judgment became ever more compelling as Berkshire's capital mushroomed and the universe of investments that could significantly affect our results shrank dramatically. Therefore, we adopted a strategy that required our being smart and not too smart at that, only a very few times. Indeed, we now settle for one good idea a year.

Warren Buffett on Business: Principles from the Sage of Omaha (ed. 2009)