Too Early or Too Late?

I'm sitting here after Angela's alarm went a-ringin' at 4:55 a.m. I was going to stay in bed, but I thought I heard someone knocking at the front door. You should never answer the door when someone knocks at 5 a.m. But I thought it was our upstairs neighbor with the 2 year old that is constantly running. I expected her to tell us to quiet down because the irony would have been hilarious. When I checked the eyehole, I thought I saw the side of her head. Turns out it was nothing. But that's not what this blog is about. The questions is as follows:

Where is the border between "too late" and "too early"?

To help you think about this: At what point do you say, "I might as well just stay up if we're leaving that early?" I've always felt the border was at about 4:30 a.m. I have other friends who think it's closer to 6 a.m. One person said 3 a.m. But I think that person was at least 50.

I'd like to know what you think.