In all sincerity though, I do replace mag springs in carry mags every 1-2 years for the CC guns I have kept long term. They are cheap (usually $3-$8 for spring or spring and follower) and I can tell a very distinct difference when I change them out. It's cheap insurance when you don't really know how much life is in that spring. If you shoot your CC weapon enough to remain proficient, you probably should change the mag springs every 1-2 years.