The problem starts with the Fair Labor Standards Act, passed by Congress in 1938, a year when nearly half of America’s labor force worked in the manufacturing or agricultural industries. We work differently now: How we get to and from our jobs, the specific tasks we perform, and the manner in which we accomplish them have all changed drastically, to say nothing of telecommuting and the growth of independent contractor relationships.

Yet many of the regulations the deparment issued shortly after the legislation was enacted have remained functionally unchanged for nearly 80 years.

One of the specific questions the department addressed in its first wave of interpretive regulations in 1940 was the circumstances under which hourly employees must be paid for breaks taken during the workday. The department made two important interpretations.

First, it determined that periods in which an “employee is completely relieved from duty and which are long enough to enable him to use the time effectively for his own purposes” do not count as hours worked.

But the department also made clear that because short rests of five to 20 minutes “are common in industry [and] promote the efficiency of the employee,” that time was “compensable” under the law. In other words, the regulations assume that no personal tasks can be accomplished in less than 20 minutes.

That expectation may have been reasonable when the idea of a smartphone was still only science fiction. But modern workers are differently situated and unquestionably have the means to use even short rest periods purely for their own convenience. Workers can video chat with their doctor, text their child’s teacher, monitor their home, order lunch, or make time-sensitive purchases, all through their smartphone’s touchscreen.

A pair of federal court cases demonstrates the problem. The 1956 case of Mitchell v. Greinetz considered whether the owner of a clothing manufacturer who required workers to take short breaks was obligated to pay them for that time. The 10th Circuit ruled that because the breaks were involuntary and work-related — they provided rest that improved the productivity of loom operators and others — they must be paid for as time worked.

Yet in 2017, the 3rd Circuit ruled that an employer who simply offered their employees the flexibility to take short personal breaks “at any time, for any reason, and for any length of time, and [even to] leave the office when they are logged off” was required to pay the employee for such breaks if they were under 20 minutes. The purpose and nature of the breaks no longer mattered; their length was the determining factor.

By applying an outdated and oversimplistic rule to modern circumstances, this holding will greatly discourage employers from offering their employees the right to take elective personal breaks.

The Labor Department should review its outdated Fair Labor Standards Act regulations to account for the substantially increased preference of modern workers for workplace flexibility. Studies show not only that workers increasingly favor more control over their working hours and working conditions, but that they place a high value on being able to use portions of the historically standard eight-hour workday for their own purposes.

The 2008 National Study of the Changing Workforce survey reveals that 87% of all wage and salaried employees would find workplace flexibility “extremely” or “very” important if they were looking for a new job. Researchers note that “feelings of time deprivation” are on the rise, even though workers’ reported levels of “work-family interference and negative spillover from work to home have been essentially stable in the U.S. labor force since 2002.” One possible explanation is that “employees’ expectations for discretionary time are rising.”

Fortunately, developments in modern technology can now be combined with workplace flexibility to allow workers to accomplish both trivial and substantial tasks without sacrificing productivity, thus leading to the potential for more satisfied employees and employers.

For that to happen, the Labor Department must revisit rules that are based on obsolete presumptions about workplace operations. Workforce rules should not be stuck in the Great Depression.

It is high time for an update to the department’s regulations that takes into account modern work environments, modern technology, and the preferences of modern workers. Technological advances allow for the possibility that employers can adjust to the changing needs and expectations of workers by empowering them through workplace flexibility to meet both their own needs and the needs of their employees.

Gregory Jacob is a former solicitor of labor and a co-author of the Regulatory Transparency Project white paper from which this commentary is adapted.