It depends on what your destination is like. When flying 'back side of the clock', I found that lights on as bright as possible really reduces fatigue. If going to an ILS equipped, or even just a well lit airport this presents no problems, and the fatigue reduction is a real bonus. If going somewhere more remote eg flares etc, I would turn the lights down approx 30-35 min from ETA, which gives time to adjust, whilst still allowing reasonable fatigue combat. Operationally this never presented a problem, even on a moonless night. As someone else has said, it is also of real benefit to suck a few minutes of gas if its available, again especially after 0200. Note: This refers to ops above 10000 so see and avoid isn't a real issue.
