Yeah....
From sometime while I was in High School, I started thinking about this and pretty much came to the conclusion that if I get in a fight I will be fighting like it is to the death. I didn't get in fights, maybe because I tended to to what I needed to avoid them and maybe because I was 6'2", fast and strong....don't know about how tough I was.
When we consider carrying, we all think about when we will use our weapon in self defense and we pretty much decide it is when there is no other choice, when it is a kill or be killed (or severely injured if you are lucky) situation.
Each incident where you resort to your weapon has become fight to the death if need be. Not saying it has to be just that it always starts that way...at least for me it would.
Trick for me is knowing I'll be thinking that way and planning on how to deal with it when the time comes.