'''This came from FortyHourWeek''' In 1930, the Kellogg corporation instituted a 6 hour work day, and a 30 hour week. This practice continued, for the most part, until the 1980s. The effect was quite pronounced; they experienced the highest worker productivity of any similar business, and exceptional worker loyalty. When the practice was discontinued, they saw a slight cost reduction, and a huge drop in productivity. While I do not advocate a 30 hour week, the XP practice of strongly enforcing the 40 hour week makes good sense, from every sane perspective. ''A couple of questions: 1) why was the practice discontinued? and 2), when it was discontinued and the "huge drop in productivity" noticed, why didn't they get right back into continuing it?'' '''And this from FourDayWeek''' Kellogg switched to a regular hour week only to see productivity, morale and loyalty plunge. ''So, why did they do that?'' Google "Kellogg 6 hour day", there's a lot of material on it. Basically, there were two main forces pushing Kellogg to an 8-hour day, neither of which had to do with productivity: Managers cited the rising fixed costs of benefits and the need to maintain "workplace discipline". Benefits in particular could be an issue: when the KelloggWorkWeek was instituted in the 1930s, companies had to pay for workplace injuries out of pocket. Thus shortened work week more than paid for itself in reduced job accidents. But now companies pay fixed health insurance costs per worker, so hiring more workers, even if they get hurt less, is a net loss. The "workplace discipline" issue is probably a red herring. Management wants to look good, they don't really care whether anything gets done. The shareholders care whether stuff gets done, but they're not on the shop floor. But a lot of the pressure to switch back actually came from employees. They felt like their status was reduced because they had all this free time now - even though wages were not significantly less. It didn't help that management tried to "feminize" the 6-hour day, suggesting that those who opted for it were "sissies" and "housewives".