Just like a good holster, a quality spare magazine carrier is also mandatory. You'll occasionally hear people say they never carry a spare magazine with the argument being that their gun holds "x" number of rounds and they won't ever need anymore. First, we don't know when or even if we'll ever become involved in a gun fight and we certainly don't know, if we do have a shooting, how many rounds we will fire. It is a phenomena long documented that people will often shoot their weapon dry during periods of high stress.

I think it would be rather disappointing to successfully defend yourself, only to be killed by your adversary's friends who hadn't rounded the corner when you started shooting. Your handgun has suddenly become a very expensive rock - throw accurately. Even if you do maintain fire discipline, it is always desirable to be able to top off your weapon via a tactical reload, just in case. For me, the strongest argument is that your serious malfunction will be cleared with a fresh magazine - remember: look, lock, strip, rack, rack, rack, INSERT, rack.

Now that I've hopefully convinced you to carry a spare magazine, the question becomes where and how. It is possible to throw it in a rear pocket so that it is available - the problem is that available doesn't mean accessible. The best solution is a dedicated magazine carrier worn on your support side. Even on my duty belt, I carry my spare magazines in this same location, this ensures that whether I'm on-duty or off-duty, I always grab for a magazine from the same location. For this reason, my evaluations of duty belt magazines holders presuppose carry on the support side, with one exception.