When I'm out on the golf course, I can usually play 'em straight and long – on a quiet day, that is. But when the wind whips up and starts to mess with me a bit, I've got to switch up to a shorter game to keep the wind from burying my handicap.
Playing stocks isn't any different. (You knew I was going to say that, didn't you?) What works on a calm day will bury you when the "weather" gets lively. When you change your game, you get much better long- and short-term results.