I've fought the urge to respond to this, as I respect the opinions of the folks that have already responded, but:
I don't at all see it compared to leaving your springs/shocks relaxed or even semi compressed on your vehicle.
It is better equated to weighing down your springs to the max for an extended period, then expecting them to work every bit as well at the very top (relaxed) end of their cycle.
In my experience, it just doesn't work that way.
I've done some testing (at least to my satisfaction with 1911 mags),and after over a year of being fully loaded the quality ones have never failed to cycle, but some have absolutely failed to lock the slide on two different 1911s.
One 1911 a Colt, and the other an Armscor Citadel.
I have only tested the 8 rd mags, so I'm not speaking as to the 7s.
I'd be in total agreement with rotating two or three times a year without worrying at all.
But I would rotate.