Spring steel, by it's very existence, doesn't just magically wear out without loading.
Thus a spring in a magazine in a WWII bunker that was never touched wouldn't suddenly shatter into pieces if you loaded it up for what would be "the first time". (caveat: assuming the Earth didn't stop on it's axis, the poles reversed and said spring steel went from -200 F to 400 F on a regular basis.
Now if it was 1,000,000th time you loaded it, yeah, you could have a problem.
Are you asking what mags are best for your AR? Or are you looking to get your hands on multiple cheaper mags and want to be able not to buy lemons?