Mike, of Mike’s Spot does a rather succinct mathematical analysis of exactly this question. Most ‘regular’ CCW folks I know carry a minimum: one speedloader, one spare magazine, one speed strip. The math would suggest TWO be the minimum.
I know, we’re mostly all about convenience. If we could carry a Wondernine 5000 with 14 spare magazines holding 30 rounds each, AND have body armor with built-in GPS calling the police and ambulance service as soon as there was bullet contact all completely concealable and no extra weight, we’d do it.
But the real world is quite different. Hey, it’s 114 today, I’ll carry the snub instead of the 1911, and maybe one five-round speed strip. In a lighter caliber with magic bullets. There!
Mike’s last line got my attention, after all the analysis:
Always keep in mind though, if ever you need to defend yourself with a firearm, KNOW that if you can’t get some good COVER, not concealment pretty early on in the fight, or your family will be reading a eulogy in your honor with a big emphasis on bravery.