Why every weekend should be a 3-day weekend

National holidays that fall on a Monday shouldn't be the only reason Americans get three days off.

It should happen every week, simply because it's the right thing to do.

Over the last several years, a number of companies around the world have made the switch to a shortened workweek, Amazon being the most recent example.

The world's second-largest retailer announced on August 26 that a select group of part-time employees would soon only need to work 30 hours per week to earn 75% pay and full benefits.

It's too early to know for sure, but there's a good chance those employees will feel more passionate about their jobs and get more done than the people working twice as long.

Consider the research of K. Anders Ericsson, one of the top experts on the psychology of work. (His research led author Malcolm Gladwell to devise the 10,000-hour rule, the idea that experts need at least 10,000 hours of practice to master a given craft. However, Anders has since criticized the rule.)

Multiple experiments done in Ericsson's lab have shown that people can commit themselves to only four or five hours of concentrated work at a time before they stop getting things done. Past the peak performance level, output tends to flatline, or sometimes even suffer.

"If you're pushing people well beyond that time they can really concentrate maximally, you're very likely to get them to acquire some bad habits," Ericsson told Tech Insider in May. What's worse, those bad habits could end up spilling into the time people are normally productive, and suddenly even the shorter weeks are wasteful.

Put into practice, shortening the work week seems to reap all kinds of rewards.

Ryan Carson, CEO of the technology education company Treehouse, has seen his employees become happier and more productive since he implemented the 32-hour work week back in 2006. Core to Carson's leadership philosophy is the belief that forcing people to work 40-hour weeks is nearly inhumane, he told the Atlantic last year.

"It's not about more family time, or more play time, or less work time - it's about living a more balanced total life," he said. "We basically take ridiculously good care of people because we think it's the right thing to do."

The company isn't struggling to make ends meet, either. Its yearly revenue is in the millions, and according to Carson, people love to come to work each day.

A similar story is playing out at Reusser Design, a Midwest web development company that changed to a four-day week in 2013. Even though the company works longer hours to make up for the lost Friday, company founder Nate Reusser says productivity and engagement have never been better.

"You wouldn't believe how much we get done," he told CNN last year, adding that the policy motivates people to work harder, similar to how people hustle to finish projects before they go on vacation.

Joe Rubin, human resources expert and co-founder of the recruiting site Crowded.com, tells Business Insider that Amazon's new policy is also a win because it's bound to attract new talent.

With a 30-hour workweek, Rubin says, new mothers and people with other obligations can maintain a stable work schedule without needing to take a long leave of absence or work inconvenient hours. By offering employees more flexibility, Amazon sends the message that life outside of work matters.

Some evidence suggests the solution isn't even in working fewer hours, but in how companies allocate people's time.

In 2008, in the middle of America's financial crisis, former Utah governor Jon Huntsman implemented a plan to reorganize the work week.

With only a month's heads-up, nearly 75% of state employees changed from working five eight-hour days to working four 10-hour days.

On the one hand, the extra day off saved public resources that were normally used to heat, cool, and power the buildings - a big win when cash was tight.

But the change also produced increased worker morale. People enjoyed the extra day off and the easier commutes, since they were no longer slogging through rush-hour traffic.

So while psychologists and work-life consultants might not know where the sweet spot of productivity exists, or if it's the same spot for everyone, the evidence suggests you shouldn't need 40 hours to get there.

For maximum productivity, people should stay mindful of when they start to feel burnt out. For everyone's sake, it might be time to cut back on clocking in.