EVERY DAY, ALL OF us struggle to stay off List B and get back to List A. It’s not easy. Remember that MIT study showing that, over the course of a week, managers spent no time whatsoever on their core priorities? Peter Bregman, a productivity guru and blogger for the Harvard Business Review, recommends a simple trick for dodging this fate. He advises us to set a timer that goes off once every hour, and when it beeps, we should ask ourselves, “Am I doing what I most need to be doing right now?”