Q: "How many magazines should you have?"For instance, consider full-size M&P 9 magazines. I have the one in my gun, the spare, eight more in the range bag that I use for range magazines, and then there are a further three or five still in factory packaging, unopened, in the safe. Should one of the ones in the range bag go wonky, I'm going to toss it and replace it with one of those.
A: "More."
If you're in some place where grandfathered "high capacity" magazines are a rare commodity (or if you're talking about some valuable C&R where actual scarcity is an issue) then by all means diagnose the problem and try and repair the magazine. But if you're dealing with a modern commodity gat with $12-$30 magazines? It's usually easiest to pitch it and buy a new one unless it's an obvious spring issue. If you're trying to re-form feed lips on surplus GI M16 mags in a world where new Magpuls are barely more than a lunch combo at Wendy's, you're practicing false economy.
