There is evidence that working fewer hours is more productive. Perhaps it’s to do with fatigue but it’s equally likely to be; if you know you can only be there for seven hours, you might be more focused on your tasks. Too many managers attribute merit and value to workers who put in long hours, rather than examining their productivity or effectiveness. Read what The Economist Newspaper had to say on the hours issue here .
For my money, people who work long hours are inefficient; managers who favourably judge employees who work long hours are lazy, ineffective managers.