I've relied on a drawn handgun on two occasions to stop an assailant, and neither time involved actually firing it. However, both were work related and not situations where an armed citizen with any sense would or should be.

There's a big difference between the situations LEOs are in and the situations armed citizens should be in, and the EDC requirements vary accordingly.

Several years ago I almost drew a weapon in an armed citizen capacity. I'd just gotten $200 from an ATM and was in a hurry to get to the AT&T store before it closed to replace my phone. It was dark (a few minutes before 9pm). I took a wrong turn, immediately recognized this was the wrong street and started turning to reverse course. At that point I saw a latino in a hoody right behind me closing fast with one hand coming out of his pocket and the other arm extending toward me. As I turned and saw him, my left hand instinctively went up to block an assault and create some more time/space to draw, while my right hand went to my hip to lift my jacket and draw. He immediately reversed direction, turned the corner I'd just made and beat a rapid retreat.

I won't swear he was about to mug me, and I don't know for sure what was going to be in his hand as it came out of that pocket, but I was clearly assessing the possibilities. He clearly recognized I was fixing to shoot him.

The fact that I'd just gotten cash at an ATM and was too distracted to check to see if I'd been followed figured heavily in my thinking. It also struck me as a total SA failure on my part. I could have avoided the whole situation with a little more care and observation after getting the cash. Generally speaking if the potential victim makes eye contact with potential assailant at a distance, and telegraphs an awareness of the situation, the assailant will just look for an easier target.

It's also an example where a gun was "used" in self defense and probably prevented a crime, but where it was never reported to the police, since no crime was ultimately completed.