Here are a few reasons why I (would if I didn't live in San Francisco) carry:
1. Not long after I got back from 2 tours of duty in Vietnam, in the 1970s when beating up or even killing gays was considered acceptable by many, LE included, I had a group of 7 or 8 thugs show up at my door all armed with baseball bats. They said that they were there to show me "What we do to fags around here". I simply reached behind the door and grabbed the shotgun which I kept there. When I racked a shell they all decided that they had someplace else to be. I never had a bit of trouble again all the time I lived in that house.
2. In the aftermath of the big earthquake here in San Francisco in 1989 the city was without power for 3 days and nights. I patrolled the building where I worked and its parking lot all three dark nights. On the second night a group of folks showed up trying to kick in the door of the neighboring business across the alley. Those folks had good hearing too. They recognized that racking sound of my shotgun from 20 feet away across the alley and they all decided that they had someplace else to be too.
BTW: as uptight as this town is about guns, our place is on one of the main streets and a lot of cops driving by saw me wandering around with that shotgun, and the only response I got from any of them were a few nods of acknowledgement.
3. I was sitting at my computer about a year ago when I realized that someone had gained access to the neighbor's roof and was coming through my landing window on the staircase going to my upper level. He spotted me just about the same time I became aware of him. The first words out of his mouth were "I f--ked up, man. All I want to do now is get out of here." As he was talking I was thinking - Here's a 20 year old kid, 50 years younger than I am, in good shape, compared me with my barely functioning COPD riddled lungs, and I am stuck alone in a large commercial building (I have the caretaker's apartment) with him. It didn't take me much reflection to decide that I kinda liked his idea. I showed him out, which involved a long walk down hallways the length of the building and aiming him at the emergency staircase. It was nerve racking for both of us, he balked about halfway out, thinking I was leading him into a trap, but I calmed him down and he left. I barely had time to recover from that incident when just a few weeks later it happened again. This time it was two guys, carrying guitars no less, who showed up at that upper window. They were polite, and stoned out of their heads. I didn't think there was any LSD still around these days, but I am guessing that is what they were on. Those guys were very non-threatening and were much easier to show out of the building, but I know that not all my "visitors" are going to be so easy to deal with. Someone suggested that I get bars for that window. My response to that is "Why should the good guys live behind bars? Isn't it supposed to be the other way around?"
4. A few weeks ago the local San Francisco TV stations were showing footage of what started out as a burglary here in the Bay Area. Two high school age gang members broke into a house that happened to have a very nice security camera system operating. The footage showed the kids come in the kitchen door. The first thing they did was to stop and arm themselves with butcher knives. They then started to search the house for valuables. Within a few minutes though they heard the occupants, who were hiding from them upstairs in one of the bedrooms. The robbers looked startled and started to exit the house, but then they had second thoughts and still armed with the butcher knives they headed upstairs to where the occupants were and with a couple of minutes kicking brought down the door of that bedroom. The occupants had moved into the bathroom and the gang members were kicking that door down too until they realized the residents were on the phone with the police. It was at that point that they finally ran away. I can think of no better demonstration of the need for effective home protection. Good clear video of a murder taking place will be small comfort to our families...
Needless to say I now have a 12 gauge within easy reach when I am upstairs in the living room or bedroom and my Glock 17 is within inches of my right hand whenever I am at my computer - the spot where I was sitting both times I had intruders show up at my window. The 10 day waiting period will be over tomorrow afternoon and as soon as it is I will be picking up my S&W M&P Shield 9MM. While I might be turning 69 years old this year, and I might not be in the best of physical condition, I just don't do victim. Never have. Never will.