Four Hours of Concentration
Unbelievable, 40+ comments and not one contrary opinion.<p>Alright, I'll be that guy. I have no trouble doing more than 4 hours worth of mentally strenuous work in a day, and neither do most of the people I work with. Frequently enough I've put in sustained 12-16 hour days for weeks on end to meet a tough deadline.<p>You'll generally find that the most successful people who are best at what they do have no trouble with this either. I'll go further and say that a large number of the people who complain about having to work more than a few hours a day are doing nothing more than rationalizing their lazy HN and/or reddit habits.