Sumdood posts a good question in a gun forum on Facebook:
I have a question for the group. I carry a .45 that uses a single stack 8+1, my question is should I carry extra mags? And how many?
Of course you should carry a spare mag. Guns malfunction, and a good portion of the malfunctions with a modern semi-automatic pistol involve problems with the magazine. You should carry a spare mag and a flashlight and a knife and a phone (and maybe a lighter and some from of medkit) because stuff happens, and Murphy rules the universe.
But that’s not the answer he gets. Rather, he receives 30+ posts which repeat, in form or another, “You need three spare magazines on you at all times because you never know when you’ll need to shoot 31 terrorists in the face and you’ll need an extra round just to be sure!!!1!!”. (The other 30+ posts denigrate the 1911 and/or .45 as a defensive firearm option. Somethings never change…).
I’ve never shot a terrorist in the face (yet), but I have had to walk through a dark parking lot when a flashlight came in handy. I have shot my carry gun in a match and had it burp on me, and an extra mag came in handy when it did. I have needed a knife to open up packaging and the other useful things that knives do. I have had one of my sons need a bandage at a moment’s notice, so having a small medkit nearby is darn useful.
Life isn’t a video game with three dozen bad guys per level and power-ups and health packs scattered around everywhere. I carry things that will help me deal with what has happened and what’s likely to happen, along with just a teensy little bit of what’s unlikely to happen (but would be really, really bad if it did) as well. If I get into a situation where a pistol and a spare mag is not enough to get me to safety and/or a rifle or a shotgun, well, then it’s time to slap a colander on my face and go full Rockatansky.