The Thinking Gunfighter, back in 2010, had another extremely thought-provoking post on why we insist on carrying so much stuff, including spare mags. Read the whole thing. Some teasers:
“But wait!” comes the cry. “What if I have a malfunction and need to clear it? That requires another magazine.”…A well made, quality firearm that has been properly maintained, using ammunition proven to feed in that gun, will not suddenly decide to start malfunctioning on you. Yes, magazines are the weak link in most autoloaders, but not good magazines…A spare magazine only addresses problems that are related to the magazine…Realistically, what are the chances that your quality-made, well-maintained firearm will pick this particular time to have a malfunction? Given that, what are the chances that particular malfunction will be the result of a magazine that is defective?
Finally: I’ll hit this point often and hard: if you carry a gun for self-defense, you have to know the law. Invest the money you’d spend on shaving a tenth of a second off your splits with Andrew Branca’s book or seminars — it’ll pay far greater dividends. Visit this link to learn more, and use the discount code “streetstandards” for a 10% discount.