“Having and not needing rather than needing and not having.”
This is the essence of the issue IMO. Particularly when carrying the spare, in most cases, costs nothing in terms of extra time, effort, or risk to the overall concealment. I clip mine on when putting on a holster. Takes a few extra seconds.
I am surprised that no one has mentioned that many of the pistol malfunctions are due to a defective magazine.
Another magazine is a better deal than trying to get a bad one going.
Another p[oint....most mag drops are really because they were not properly latched to begin. When putting that mag in, slap the hell out of it to be certain it is properly latched.