I'm not being critical here of any one who wishes to carry extra ammo. If that's one's preference, then they should do it. It's their right.
Having said that, while I understand the motivation based in "be prepared for anything", I've often wondered what proportion of self-defense events involving guns actually require reloading?
That is, what proportion of gun users other than LEO's and other professionals, that is, your average person just trying to stay alive in a defensive situation, who've been in a life threatening situation involving a gun - have actually used spare ammo or wished they'd had it because they needed it?
I'm asking this more to judge whether to carry extra rounds, and if so, how much.