I’ve been saying for as long as anyone will listen to me that I can do a maximum of four hours high-quality knowledge work per day. Add on some time for emails and ‘sync’ meetings, and five seems about right.

The difficulty, of course, is the financial side of things. If you’re employed, will your employer pay you the same amount for working fewer hours? (even if productivity increases). And if you’re self-employed, will clients sign-off contracts that stipulate five-hour days?

The eight-hour working day is a relatively new concept, widely accepted to have been cemented by Ford Motor Company a century ago as a means of keeping production going 24 hours a day without putting undue demands on individual members of staff. Ford’s experiment led to an increase in overall productivity; but proponents of five-hour days, including Californian ecommerce business Tower Paddle Boards and German digital consultancy Rheingans, say they experienced a similar phenomenon when they moved to compressed-hour models.

Like Corcoran, Tower CEO Stephan Aarstol says he was startled by the results when the business adopted a five-hour working day in 2015. Staff worked from 8am to 1pm with no breaks and, because employees became so focused on maximising output in order to have the afternoons to themselves, turnover increased by 50 per cent.

Source: The perfect number of hours to work every day? Five | WIRED