It depends on my mental state, and what I've already decided to do or not.
If it's last day of deer season and I have determined that I am killing the next legal animal, period, then about 2 seconds is all it will take.
If it's opening day and I'm being picky and a bit lazy, I will hesitate a lot. It usually takes me a "few days in the woods" to get that sixth-sense killer instinct back anyway.
I did once lay in a field after a stalk for over 3 hours, just waiting for the big one to stand up and give me a nice easy 40-yard shot.
