Should you have to swap out magazines, speed may be a good thing. While there is no hard and fast source for the “average rounds fired in a gunfight” when dealing with personal defense use, several large law enforcement agencies have documented that the majority of officer-involved shootings expend five or fewer rounds.
Even with that in mind, scoffing at the need to carry a spare mag is countered by the popularity of today’s limited capacity single-stack semi-autos coupled with the possibility of accidentally ejecting a loaded mag or having a magazine-related failure — any of the preceding making a spare stick and training to use it rapidly a desirable skill set.
In the above video from T.Rex Arms, Lucas Botkin breaks down the drills he uses to get back on target quick while factoring in reloads. If you are discouraged by the fact that he doesn’t work a slide-lock reload at first (“ahh, this is a gimmick,” says the guy in the back), give it a minute and he progresses to that, performing it almost as fast.