How long can you go without social interaction? How long can you go without alone time?
Obviously every human being needs both, but each of us has our own individual threshold. Also, a lot of times it depends on the situation.
What situations drain you the most--clubs, seminars, a weekend alone, parties, etc? What energizes you? How long does it take to recover from a draining situation?
Me: I'm an ambivert. A full day at home with no people may become tiring. I usually need to go out for an hour to an hour and a half to refill. Going out doesn't necessarily have to be with people--though usually it would. Sometimes it's a just a drive or a trip to the grocery store.
After three hours of stranger/non-close friend interaction, I need *at least* three hours to recover. With my very closest friends, I can go a full day feeling energized, but will need maybe an hour of alone time afterwards.
I thrive on close friend interactions, alone time, and creative public speaking (not too much mingling afterwards). Ideally, to keep myself energized, I would like day of both interaction and quiet time. For instance, spend the morning and afternoon alone, be with close friends until the evening, and spend the last hour before bed by myself.
Then again, too much change in activity is also exhausting. Sometimes a whole weekend all by myself sounds fantastic. Sometimes not.