Sometimes I carry an extra in my pocket. If I'm O/C my holster has a pocket for extra mag. I have a mag holster, but don't use it a lot as between my IWB holster, my cell phone, my knife case, keys, and then trow in the mag holster on my belt, it's just too much weight. Not comfortable. Besides my SR9 holds 17+1 rounds.
If this gun bill goes through I will be like a lot of people, looking for 10 round mags.