spat
.700 Nitro Express
If they are quality springs it doesn't matter at all.It's actually the opposite, it's the wear and tear that is what makes springs weaker.
You should have a dedicated known-working magazine or two if you are going to rely on it.
All other magazines should be for practice/playtime.
Remember the valve springs in your car engine all spend half their lifespan compressed, and they see more cycles in a minute of run time than your mag spring will see in the next 100 years.
When was the last time you had go replace valve springs ?
The only time a spring wears out is if it's a cheap POS that's used outside of it's properly designed service envelope.