If I'm going to have a gun fight, I will take a brand new never loaded Glock, Sig, or Kimber mag over any mag in the world that has been left loaded to capacity for 25 years, or even one year. A guy I certified as an instructor a few years back who owns a security firm brought a CZ over the other day with feeding problems. The spring tension was almost non existent. I told him to get a new mag, he did, and no more problems. You may say its a myth perpetuated by spring makers, but I'd disagree - also I have a good friend who is a gunsmith. I don't know, sometimes facts are good to have, and sometimes real life experience plays a different hand, who knows eh? For reference, check out the FAQs: http://www.gunsprings.com/1ndex.html Also, it is good to cycle your bullets regularly. The reason I never send the same bullet home twice ever is that the kinetic energy expended when the slide slams forward to chamber the round is enough to weaken the crimp or potential pressure that bullet can contain significantly. A bullet puller is a hammer like tool that you put the bullet into when you've screwed it up seating the bullet too deeply, and you want to pop it out and reseat it. All you do is put the bullet in a bullet case holder inside a plastic container on the hammer like object, give it one swift swing down on a table and out pops the round. That's all it takes. So, every time you send a round home, you give it at least 20% of what a bullet puller puts on it in terms of kinetic energy that loosens the crimp.