The way I was always told by some LEO friends is to make sure there is only one side of the story to be told.
That is... morbidly hilarious.
I've got a Remington .308 back home for hunting and whenever we get out to the larger ranges. I am not a fan of the .45 for self defense, but it is fun to shoot. Perhaps for someone with the wrist and hand strength and dexterity to efficiently and effectively double tap, but I certainly can't unless I'm on a .40 or a 9. That said, I choose the .40. Its a good middle round, can still pack a punch, and still has plenty of quality options (though I will say Walther won me over years ago).
About home defense, I've had my decision made for a few years now. First, no warnings, and certainly no warning shots. A live round is a live round, and no one can predict where that "warning shot" will end up. Could be a thud into the wall, could be a gas line, could be the dog, could be the daughter. While you were trying to scare off the first attacker by giving away your position, the second attacker was flanking you or running into the room of your loved one(s). That said, you shoot to neutralize the threat. No buckshot, no blanks, no rubber, no leg shots, no arm shots, no damn warning shots. The attacker will receive 2 rapidly placed round to the thoracic cavity. If they continue to be a threat, they will receive 1 round to the head. Once all threats are neutralized, 911 will be called (if it has not already), provided my name, the address, the quick story, and the number of casualties. I will remain on the line as I assess all casualties, triage as indicated, and provide what ever treatment I can to those who do not present obvious signs of death. If I can't prove that the attacker is deceased secondary to trauma instead of an arrhythmia from a pre-existing condition, I will do compressions until EMS arrives.
A friend of my mom always bragged about his guns. One day he had told her that he always keeps his bed-side handgun loaded in this order: blank, scatter, scatter, the rest normal bullets. Folks, if you do not trust yourself to make a decision, be it right or not, on that first shot, then you do not need a lethal weapon in your hand.
