The longest I have been awake was 6 days straight, a few times, but only when manic. I dunno I started having insomnia around 12 year old and it's never got back to normal, but I function just fine with three or four hours, don't feel tired at all. My bf though loves to sleep, and loves to sleep in very late, so that kinda sucks, hard to compromise there, I only ask that he get up early with me one day every week or two.. Early meaning around 10 am or so.

I hate waking up at 4:30- 5 am cause there is literally nothing to do. I usually go work in my garden at 5 am in the summer, not too hot that early and I think all the bugs are still sleeping.