They call them “CrackBerries” for a reason—in today’s busy world, smartphones can seem impossible to put down. The good news is, there's a way to fight your addiction. Research by the Harvard Business School suggests that turning off your device for just one evening a week will make you feel happier and improve your performance at work. The researchers studied 1,400 employees of the Boston Consulting Group for three years. The staff was banned from checking work after 6 pm one evening per week, during what was termed “Predictable Time Off” (PTO). Naturally, managers were wary of the rule at first—and some workaholic employees even refused to participate. But those who did utilize PTO said they spent more time with their families and working on their social lives, and found it led to a happier work environment. After three years, 59% of those who participated in the experiment agreed with the statement “I am excited to start work in the morning,” and 78% said they felt “satisfied” with their jobs. Comparatively, only 27% of those who didn't participate were excited to work in the morning, and only 67% felt satisfied. Professor Leslie Perlow, who came up with the idea for the study, concludes, “By being constantly connected to work, they seemed to be reinforcing—and worse, amplifying—the very pressures that caused them to need to be available.”