For pistols, I average 3 magazines each. I have more than that for 45acp, but that's only because I had some leftover when I sold a 1911A1 and when I bought my next one, it came with more. I have 4 on one gun because I had 2 8 round mags, but I didn't like the feel, so I bought 2 10 round mags. I don't carry a 2nd magazine with me so that's not important. I have a 2nd for the range or in the house if I need a 2nd. I have a 3rd, strictly as an immediate replacement in case one of the first 2 were to break. This way I have my 2nd one on hand while the replacement is on order.