If you carry you HAVE to have extra mags, otherwise you are not being serious about your training 99% of malfunctions happen due to ammunition so heaving only one mag does you NO good (the one inside your gun).
S&W 442 w/ spare SafariLand speed loader. Add a G27 w/ spare G22 mag and NAA 22LR mini revolver when going to "the city".
Yeah, a little paranoid about Big Easy - no offense.
Two extra mags. There are many times I think I'll take just the pistol with the mag in it on a convenience store run. Then, I convince myself that's a stupid idea and put the extra mags on anyway.