Cloud had an excellent post on work hours and productivity from the standpoint of a manager. The essence of the post is that everyone has a work limit beyond which they are no longer productive or -- even worse -- they become counterproductive, as errors accumulate. Cloud argues that long hours are unnecessary and that with careful planning and partitioning large projects into smaller pieces one should seldom have to work long hours to meet a deadline.
The comments are also very interesting, as usual, and I encourage you to check them out. One comment in particular mentioned how they, an academic in a theoretical field, simply don't work when uninspired; instead they wait for inspiration to hit, at which point they work very long hours and get a lot of work done... I, however, like to think, as the saying goes, that inspiration comes from doing, not the other way around.
The post and the comment reminded me of a recent conversation I had had with a graduate student of mine. He interviewed for a postdoc with a good group a few months ago, and secured the position. Of course, his future boss wants him to start as soon as possible. The student and I agreed long ago on what he needed to do before he graduates. Before graduation, he needs to finish a major part of his project, we need to write and submit a paper from his project which will include this major technical part, he needs to write up quality documentation for his code, as well as obviously write his dissertation (the dissertation should not take very long, once all the relevant papers are written up). The goal was to have him tentatively finish everything by the end of summer.
Now, the student has been stuck on a technical issue for a while now, and is not making much progress on either calculations or paper writing. I told him to go work on code documentation or those parts of his dissertation that don't require this particular set of data. Since he needs to graduate sooner rather than later, this would be a good use of his time and should alsohelp with the technical challenge by freeing his mind and letting it gnaw on the problem in the background. However, the student basically refused, saying that he could do all that later (cobbling code documentation at the last minute will not produce a quality document, that I know for sure) and that he couldn't work like me (?!); instead, he said that he preferred to work on one thing at a time, immersing himself completely, until he is completely done.
Can't work like me? Yeah, because I looove being interrupted all the time by the various things I have to do, and I could not possibly prefer to work on one thing at a time, immersing myself completely, until I am completely done.
Working on one thing at a time, for as long as you need to or feel like it, IS A LUXURY. It means there is no one else who depends on you; no one to pick up from school, make dinner for, or wipe their butts; no one who is on your team at work and needs your part of the project to get their own assignments done. I cannot tell you how many times it happened that I am in the middle of something exciting at work, and all of a sudden it's 5 o'clock, time to pick up the kids and go home to make dinner. My preference to stay immersed in my work is completely irrelevant.
There is something intoxicating about working long hours on something challenging. I have been known to really enjoy pulling all-nighters, they make me feel strangely alive. It's probably the adrenaline. But, after an extended period of such work, I invariably crash. I can no longer routinely put in long hours or pull all-nighters followed by comatose periods, because it's not fair to my husband, who then has to take care of the kids, and it is not fair to my kids. Recently I had a really busy period because of the conference I was organizing. This period included several weeks of working very very long hours, a week where I did not see my kids at all even though I was in town, followed by a week to recuperate. I don't have the right to put this much strain on my family on a regular basis.
Lastly, there is sleep. I have had students who work regular hours and those who work and sleep erratic hours, in bursts. The most productive people have been those with regular work days -- come in the morning, work hard, go home in the evening and relax. People with erratic sleep and work habits ended up not being as productive overall as they could have been, because they'd get sick more often than average and were consistently pushing themselves beyond the optimal efficiency limit. In my own personal and professional lives, there are many balls to juggle. I need to be in fighting shape for my family, for my students and coworkers, which means I need to be healthy and rested, both of which require enough sleep. Not that I am getting as much sleep as I need as regularly as possible, but I'm getting better at it. Sleeping enough makes all the difference to my energy levels and my mood.
Adapting your modus operandi to accommodate all the different people who depend on you for different things is not a personality trait (I particularly resent it when people imply it's somehow a women's trait). It is about recognizing that your life is no longer all about you and what you want, about accepting your responsibilities. It's called being a grownup.