The compressed spring thing is not supported by any science that I'm aware of. The only thing that can kill a spring is dirt, corrosion, constant loading and unloading, or overextension.
I will have to disagree when I just talked to the Natick science rep here. Again constant compression of a spring is constant use, according to his sources. If I can get the report he cited I will send it to you.

In any case, we both agree that rotation of magazines is important, do we not?

Tom