A few months ago, a newly minted lawyer appeared at a question and answer session I attended in order to share his first impressions on life as an associate. When asked about communication with partners, he explained the importance of being mindful of their schedules and preferred methods of communication. One partner put the following question to him: “If you are not in the office on the weekends, how am I supposed to communicate with you?” I have the feeling that the young attorney’s experience is not different from that of many workers who are encouraged or expected to work weekends or work long hours. (I hesitate to use the phrase “work overtime” here because it connotes that the worker will receive additional pay, which is not always accurate for employees who aren’t hourly.) When asked what the ideal “hard worker” looks like, many people might respond by saying that it’s the employee who works weekends, shows up before the boss arrives, and leaves long after he or she has gone home. But as Sara Robinson pointed out in an article featured on Salon last week, working long hours doesn’t translate into greater productivity and more profits, which may be a signal that something is amiss in a society that works 55 hours a week on average. Robinson makes a bold claim: “Every hour you work over 40 hours a week is making you less effective and productive over both the short and the long haul. And it may sound weird, but it’s true: the single easiest, fastest thing your company can do to boost its output and profits — starting right now, today — is to get everybody off the 55-hour-a-week treadmill, and back onto a 40-hour footing.” While there are exceptions for when an employee works longer hours for a brief period—to meet a production deadline, for example—Robinson says that the general rule is that a 40 hour workweek generates the greatest good for both the employee and the employer. As I read Robinson’s statement, I took a quick mental trip back to Economics 101 and thought about the concept of maximum total utility. Could it possibly be true that 40 hours per week is the tipping point in terms of increasing marginal utility—not just for the employee, but for the employer? I don’t have the background in economics to venture an educated guess, but Robinson persuaded me a little when discussing the origins of the 40-hour work week. While the unions initially pushed for shorter work weeks as early as the 19th century, businesses who gave into the union demands saw rises in productivity, and studies conducted in the early part of the 20th century confirmed the shorter work week benefits. Economic reasons for returning to the 40-hour week dovetail nicely with the social reasons for leaving early, such as allowing time for workers to cultivate personal and professional relationships outside of the office. The idea that family time must be routinely postponed in pursuit of the almighty dollar is particularly concerning, especially when one considers the number of married-couple families where both individuals work outside of the home. Department of Labor Statistics issued last March show that both spouses were employed in 58.1% of the families of married couples with children surveyed in 2010. While the statistics are silent about the number of hours each parent worked and when each parent worked them, it seems possible that at least some of these families would experience a great deal of stress from two parents working long hours. When we “overvalue” time spent at work—thinking it makes us far more productive and valuable to our employers than it actually does—we run the risk of discounting the core of what drives many of us to work as hard as we do in the first place: caring for our loved ones. That risk alone should be enough to send us all home shortly after five.