We probably have one of the longer legal days out there, 18 hours on duty with 12 hours aloft. Course, the whale has good bunks. Occasionally, we are asked to perform a ferry flight after all of that time (in the US, ferry flights are not subject to duty limits). While I can expound for pages on this, what makes this work, moderately well, is that the company has an iron clad fatigue policy. The second anyone says the word fatigue, we walk off of the airplane, and the day is done. Personally, that happens to me about once a year. That's just my airline though, but if you are too tired to fly, you are too tired to fly.