While trying for just after sunset works well, theres something to be said about shots in the dead of night as well if you can find a decent location with a decent subject.
Some f'rinstances..
11:57PM
10:30PM
8PM (Maine in January, sunset is like... 4 in the afternoon then)
3AM (again, Maine winter... in summer thats almost sunrise!)
Could some of those shots have been improved aiming for around sunset or sunrise? Maybe, but they certainly wouldn't have been the same shot, and at least one would have only been subjected to a gloomy sky in lieu of a dark one.