"All of us in our lives make decisions about when to do things. 'When should I work out? When should I do this kind of work, when should I do that kind of work? When should I start a project, when should I abandon a project?' ... and the best time of day to do something depends on what that something is," said Daniel Pink, a New York Times bestselling author whose new book is called "When: The Scientific Secrets of Perfect Timing." Pink, who was trained as a lawyer and now runs his own company as an organizational management expert, argues that doing certain tasks either during the "peak, trough or recovery" periods of our energy levels, can be more effective, whether it's when to hold a meeting to get the best ideas or when to exercise to get a fulfilling workout.