if you arrive at frankfurt before 6 am local time you have to pay a penalty of some 1000 euro's, so we always try to land there after 6 am. sometimes atc is giving you a shortcut for final and all your efforts to be "late" are invain!
so if you come from far east like i do set your speed to arrive at least at
6:10 am, that covers for the shortcut atc might give you.