My first two years in Germany, I routinely "worked" 100 hour weeks. That included Staff Duty Officer averaging twice a week.
As a Systems Maintenance Officer (a thankless job if ever there was one), I was with my mechanics on site for roughly 70+ hours a week. On Friday afternoons, the Group Commander liked to visit our tac site (and motor pool) about once every two months. Naturally, I was usually the only officer on site, so I got to escort him around.
I didn't mind it, he saw my soldiers busting their tails, though he chastised me for wearing coveralls...officers weren't supposed to get their hands dirty. I could see the gleam in his eyes, which said to me "keep up the good work LT, I'm a colonel now, and I have to perform the role." lol
During tac evals on our base (Hahn AB - we were Army Air Defense tasked with short range air defense), I was in the Wing CP (as the Army Liasion Officer) for the entirety of the eval...all four days. I didn't mind, the only other officer who had the necessary security clearance was the Battery Commander. I was able to nap a bit after midnight, and I brought several sets of fatigues with me.
I'm not saying that continuous 100 hour work weeks are optimum, just a necessary part of the mission from time to time.