Companies are more productive when they stick to a 40-hour week. This article explains why.
From the article:
Unions started fighting for the short week in both the UK and US in the early 19th century. By the latter part of the century, it was becoming the norm in an increasing number of industries. And a weird thing happened: over and over — across many business sectors in many countries — business owners discovered that when they gave into the union and cut the hours, their businesses became significantly more productive and profitable.
Even Henry Ford, who was definitely some kind of socialist, profited from this knowledge:
By 1914, emboldened by a dozen years of in-house research, Henry Ford famously took the radical step of doubling his workers’ pay, and cut shifts in Ford plants from nine hours to eight. The National Association of Manufacturers criticized him bitterly for this — though many of his competitors climbed on board in the next few years when they saw how Ford’s business boomed as a result. In 1937, the 40-hour week was enshrined nationwide as part of the New Deal. By that point, there were a solid five decades of industrial research that proved, beyond a doubt, that if you wanted to keep your workers bright, healthy, productive, safe, and efficient over a sustained stretch of time, you kept them to no more than 40 hours a week and eight hours a day.
Basically, it seems that this was accepted knowledge for decades – until some time around the 80s when constant overwork became seen as a sign of passion and a desirable tendency in employees.
Go read the whole thing – it is excellent.
Your take
What about your workplace? Are people allowed to work 40 hour weeks or is overtime more or less mandatory? What is your optimal number of working hours per week? Please write a comment, I’d love to know your take.
Someone sent me a link to this Forbes article about 
