I operate under the premise that anything worth shooting once is worth shooting two or three times.
Very important in my experience is being able to call the shot. Knowing where the crosshairs or front sight were the moment the trigger broke is very instructive and lets you have a pretty good idea of what's going on. I've had deer show little or no reaction to the shot but knew that I killed them because of that flash image in my mind. But knowing their reactions is important as well. I once aimed to shoot a buck in the heart at about 50 yds with a .30-30. He jumped and kicked the way then do when heart shot, but after that jump he stopped to look around. Recognizing something different I shot again and he took off into the brush. Come to find out an unnoticed branch deflected the first shot into a hoof and the second got him through the lungs.
