one of my very first jobs was working in a machine shop and the very wise owner explained how springs and metal work. you can bend metal, which basicly what springs do is bend, this is work and makes the atoms of the material rub against each other generating heat. the heat weakens the structure. when the piece of metal is not moving, in the case of springs compressed or decompressed, there is no heat being generated. so a spring doesnt care if its compressed or not.
you can see the effect yourself by bending a coathanger wire back and forth and feel the heat it generates at the bend. bend it once and leave it there is no further heat generated. same for springs.
so anyone claiming that springs need to rest or at full compression fatigue dont know anything about metal working or the properties of steel.
im no expert by any stretch but its basic metalurgy
when you get someone that says their mags dont work full loaded its because the springs are worn out or are faulty and being compressed beyound their operating range. you see this a lot with cheap foreign magazines and cheap US made ones. its not however because the springs "need to rest" thats just foolishness.
a quality magazine will function at its rated load for as long as needed or until decays from rust
one last thing. you dont take the leaf springs out of your car to "let them rest" or jack the body of the frame at nite so those last few pounds dont cause a rough ride...
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent