All other times I carry two spare mags.
I carry two because it helps balance out the weight and helpls to keep my belt straight. One of the tells that someone is carrying is that the wearer's fly will be at an angle, especially with IWB. The mags on the opposite side help with that problem when OWB.
My mag pouches are all Uncle Mikes with velcro cover flaps. Even with IWB and a tucked shirt, it's hard to tell what's in the mag pouches. In this day of everyone having so much electronic hardware attached at the hip, my mag pouches are probably mistaken for phones more than not.
