Crunch Mode

Via REDDIT: Why Crunch Mode Doesn't Work: 6 Lessons.
Here is the Executive Summary:

When used long-term, Crunch Mode slows development and creates more bugs when compared with 40-hour weeks.

More than a century of studies show that long-term useful worker output is maximized near a five-day, 40-hour workweek. Productivity drops immediately upon starting overtime and continues to drop until, at approximately eight 60-hour weeks, the total work done is the same as what would have been done in eight 40-hour weeks.

In the short term, working over 21 hours continuously is equivalent to being legally drunk. Longer periods of continuous work drastically reduce cognitive function and increase the chance of catastrophic error. In both the short- and long-term, reducing sleep hours as little as one hour nightly can result in a severe decrease in cognitive ability, sometimes without workers perceiving the decrease.

This excellent article goes into interesting detail.

Here are the 6 lessons:

• Lesson One, then, is this: Productivity varies over the course of the workday, with the greatest productivity occurring in the first four to six hours. After enough hours, productivity approaches zero; eventually it becomes negative.
• Lesson Two, then is this: Productivity is hard to quantify for knowledge workers
• Lesson Three is this: five-day weeks of eight-hour days maximize long-term output in every industry that has been studied over the past century.
• Lesson Four is this: At 60 hours per week, the loss of productivity caused by working longer hours overwhelms the extra hours worked within a couple of months.
• Lesson Five is this: Continuous work reduces cognitive function 25% for every 24 hours. Multiple consecutive overnighters have a severe cumulative effect.
• Lesson Six is this: Error rates climb with hours worked and especially with loss of sleep . Eventually the odds catch up with you, and catastrophe occurs. When schedules are tight and budgets are big, is this a risk you can really afford to take?

I must confess I have gone against these lessons on a regular basis (through my own initiative or under direction/suggestion of management).

The takeaways for me here as a knowledge worker who always tries to maximize his own individual productivity, is greater awareness of negative time effects upon my efforts.

I recomend this article to all