Please, enough already with the "what if" scenarios....One should know his carry pistol, his capabilities under stress to the letter.....
It might be that I just don't "get it"...The way I dress most of the year really isn't conducive to extra gear...Concealment for a handgun is full time for me, let alone adding a mag or two....
You sound like you're attempting to justify not carrying extra mags by emotion, not logic. You seem to be forced (?) in not being able to carry more, so you're trying to tell yourself "I don't need any more..." Not good way to look at it, imo.
Secondly, no one knows how they'll act under stress, until that stress happens; you can imagine all you want (which actually helps, but is still not the real thing), but until it happens, you don't *KNOW* how you're going to act, nor how accurate you'll be. It's just a fact of life.
Therefore, I say, if you can do it, then bring at least one extra magazine with you, no matter how much your current mag holds inside the gun. I'd suggest bringing 2, if possible. But then again, I'd just take one extra mag, and then save room for a back up gun (like a sub compact) in my pocket or ankle.
Glocks are nice for hi-cap (high capacity) magazines. You can have 15 rounds (+1 in chamber) in a Glock 19 (9mm), or 17 rounds in the magazine (+1 in chamber) in a Glock 17 (9mm). Or, if you really need hi-cap backup, you can buy the 33 round magazines and put them in any Glock 9mm model!
I am personally getting a Glock 20 in 10mm caliber. It holds 15 in each magazine, and 1 in chamber. I'll also have a backup 15 round magazine, and when I get the chance, I'll have a Glock 29 (also 10mm, but sub compact - smaller) for my back up gun, most likely hidden in my other pocket.
It's always best to prepare for bad scenarios. The ones that die in bad scenarios, are the ones that went by statistics (how crappy those are to listen to...) and thus didn't prepare beforehand; they didn't think it'd happen to them, but when it did, it was too late... and now they're not alive to all tell us how dumb it was for them not to prepare for the worst in the first place.
If only those that died could speak from the grave... then many more people'd learn not to listen to stupid "it's rare" statistics. When it's happening to you, I bet you're not going to be sitting there saying "But, how can this be! It's so rare! Why me?!" . . . Hey, it has to happen to someone, right?
"A prudent person foresees the danger ahead and takes precautions; the simpleton goes blindly on and suffers the consequences." - Proverbs 22:3