An unloaded magazine will reliably be as useful as a small metal stick for defense. And an unloaded gun makes for a great paperweight...
Constantly loading and unloading of the rounds in a mag will wear down the spring. Leaving a mag loaded will not. Springs fatigue through "cycling", not constant loading.
Leave them loaded, and in a safe place. A strong spring is a reliable spring. A reliable mag leads to a reliable gun, as most Failures to Fire (FTF) are mag-related.
Then get a nice matching 9mm or bigger for defense, and practice a lot with the P22.