I'm of the somewhat odd mind that if I can do my job in 40 hours then I am going home at the end of the day. If someone else needs 50 hours to do their job, I don't feel obligated to hang around the extra 10 hours a week just to make them feel better. If there is something I can do to help keep the project on track, even if it means I go over 40 hours, then I generally will do it.
In terms of development I am one of those people that tends to be at least twice as productive as anyone else on the team. I have completed numerous tasks, helped others with their issues, and mentored junior developers all in a 40 hour week. I generally don't have to go over and if I knuckle down and get the work done I can do a lot in a surprisingly short amount of time. However, my productivity drops dramatically as I get tired. At 14 hours straight I am pretty much writing 80% bugs. That's with a good amount of rest the night before. I then have to spend the next two or three hours of the following work day undoing the bugs I wrote the night before. I simply do not believe more hours is more productive.
While the 40 hour work week may seem arbitrary, there seems to be something to it. I've seen shops that routinely work their people slavishly and I see very little in terms of creativity or innovation. Code quality tends to be bad and bug fixes are endless. There are days I'm surprised those places actually write any functional code at all. On the flip-side, I have worked at a client site where the regular employees routinely worked between 30 to 35 hours per week and it was also frustrating. There was no sense of urgency and having employees effectively miss a full work day worth of hours had about the same impact as having employees work too many hours.
If someone likes working long hours I think that is fine. I have met very few people who are actually effective when they are working every waking hour.
From a career standpoint, I don't think long hours means better opportunities. I know senior people who routinely work 60+ hours that have peers that work a standard work week. To be honest, I kind of admire the guy who can do the same job in less time. I will say that it is damn hard to climb the corporate ladder if you're never willing to put in the time. My general philosophy is that most things can be done in a 40 hour work week and I'll be right there with you walking out the door at quitting time. However, if there is work to be done or a problem crops up, I will work to get the problem solved. Some things, no matter how tired I am or how long the day has gone, simply cannot wait until tomorrow. If I were evaluating one of my subordinates I'm not going to look at how many hours they worked per se but I am going to want to know if they've used their time efficiently and if they've been willing to take some extra time when it was needed. I am not so impressed by people who will leave at their usual time while we're in the midst of a crisis.
[ February 20, 2007: Message edited by: Jason Cox ]