I tend to alternate between two schedules for a week or more at a time:
12-2AM: Life is busy and I've lost track of time but I am always in bed by 2AM.
10PM (ish): My body is in tune with the sun and so I'm waking up at 5-6AM by the light. I find I usually need naps to make it through the day but this schedule is usually my most productive. I get onto this schedule when I crash early from staying up late for an entire week or when I spend time outdoors (e.g. camping for a week in Yosemite under the stars).
12-2AM: Life is busy and I've lost track of time but I am always in bed by 2AM.
10PM (ish): My body is in tune with the sun and so I'm waking up at 5-6AM by the light. I find I usually need naps to make it through the day but this schedule is usually my most productive. I get onto this schedule when I crash early from staying up late for an entire week or when I spend time outdoors (e.g. camping for a week in Yosemite under the stars).