It really depends on the type and brand of firearm, and also what spring, be it the main spring, mag spring, sear spring so forth and so on.
As far as extending the life of a spring goes, you can strech it out slightly and let it "re-memorize" the length by sitting for a short time then put it back in what ever. That will help for a short while but time and use will wear out even good springs sooner or later.
some springs age do to unknown reasons.I am rebuilding 5 rifles from the 1880
the firing pin springs are all good.I have 45 magazines from the 1920s that still work.my 1903  still shoots good.so they should last.