Most police departments fire their duty ammo every year and replace it with factory new ammo. It's a good idea to do this for your concealed carry weapon too- you don't want to press the trigger and hear *CLICK* at a critical moment, do you?
It is important to have two types of mags and ammo- one designated training set and one designated carry set. Training mags get tossed around at the range, run lots of cheap, dirty training ammo and it's OK if they get beaten up. They should be marked or painted to make it impossible to confuse them with carry mags.
The logic behind this is that you keep the gear you depend on to defend yourself pristine. Feed lips on mags can get bent when mags hit any hard surface just so- including the ground. If this or other damage happens the mag may be good for training but will be more prone to an occasional malfunction than one that has never been dropped. Why take an unnecessary risk by using equipment that is more likely to fail?
If you clean your gun after some range time and load it back up with carry ammo afterward (such as Hornaday Critical Duty ammo, projectile pictured above) many would suggest firing your carry ammo once every 12 months. This stems from concern that solvents will penetrate the primer pocket and render the primer itself inert. That has the potential to be an urban legend though- instead think of it as practice. You may run across problems right under your nose by practicing with your carry rig. Tomorrow I will give the lowdown on my own scary equipment failure, analysis and response.