Old-school wisdom says to store your magazines unloaded when they’re not in use to save the springs, or even to not load them to full capacity. Old-school wisdom apparently does not carry a gun every day nor have a home to defend. Internet scientists say that magazine springs are impervious to damage from being loaded for extended periods of time and point to (probably the same) anecdote of a 1911 that was loaded back in nineteen dickety two and still “worked just fine.” These same internet scientists insist – knowing that a recoil spring can last 2000-5000 rounds or more – that only the repeated loading and unloading of a magazine is what causes magazine springs to wear out.
Shadetree Armorer has done a great video which adds more data points to a contentious argument.
Never mind that it would take 30,000-75,000 rounds to put 2000-5000 cycles on a fifteen round magazine (if you shoot all the ammo you load) and that round counts in that range could very likely wear out the gun as soon as the magazine spring. Never mind that shooting 30,000+ rounds through one gun with one magazine is probably something approximately 0% of gun owners ever achieve. Is either camp right?