There is much debate on leaving magazines loaded and for how long. I like having a surplus of magazines for the guns I really like and intend to keep. This is added security in case the firearm is ever discontinued. Then I don't have to worry about trying to find magazines when they are hard to get and expensive. Many sources say that it is actually harder on the spring in the magazine to be loaded and unloaded, than it is to just leave the magazine loaded. When leaving a magazine loaded, the spring will lose a little bit of its temper but not enough tension to compromise its reliability for many many years. Having multiple magazines also allows me to error on the side of caution and allows me to rotate out my carry magazines to give the springs a break. I like to follow the 90 day rule that many law enforcement agencies use. Every 90 days I will empty the mag in my gun and my spare magazine that I carry and rotate to two different magazines. David Cohol of Mec-Gar magazines also suggests following the 90 day rule. George Harris of Shooting Illustrated magazine writes that he has used magazines that were loaded for over thirty years and they ran flawlessly through his firearm. This seems to be the case for many people, but with the minimal effort it takes to rotate magazines, I figure it is worth my time for piece of mind. I keep track of my magazines by marking the baseplates with the initial of my last name and a number.This allows me to keep track of which magazines I am rotating through, instead of possibly rotating through the same four magazines each time. By marking the magazines, this also keeps me from mixing my magazines up with others when shooting with other people.