Most people probably don’t change out their CCW loads enough. But one thing you should keep in mind is that primers and powder are susceptible to extreme heat, cold, and moisture. The ammo you keep in your gun safe in the box is hardly under the same conditions the loads in your weapon encounter during day to day carry.
In cool, dry storage, primer shelf life is indefinite. Heat and moisture is what can ruin them. The day to day carry your CCW ammo experiences is unlikely always going to be cool and dry. Carrying during the summer, your gun is going to come in contact with sweat and oil (which, by the way, have probably soaked into your holster too). That means the same for the ammunition in your weapon.
Also, during the summer, you may want to visit establishments or events that do not allow concealed carry, which means (if you’re like me) you’ll probably leave your pistol in your car. Now, we’ve all seen the coverage about leaving animals in hot vehicles—it truly gets hot in your car during the summer months. But high heat (and not to mention sudden fluctuations of temps from inside at 70 degrees; to a hot vehicle of 90+) can cause problems for primers and powder, thus causing unreliable ammunition.
If you carry during hunting season, you’re likely to sit in your deer stand in the cold (maybe even the snow, depending on where you live, or where you hunt). Or, you might even encounter having to expose you (and your CCW) to water—crossing a creek or stream, or maybe even falling in accidentally. Smokeless powder and primers that come in contact with moisture are not reliable.
So all that to say: Replace your self-defense ammo every six months or less.
The best thing to do is take your weapon to the range and discharge the “old” loads. Now the ammo isn’t old; it just needs to be replaced with ammunition that hasn’t been in your weapon all summer (or winter). There are two benefits to this: 1) fresh, reliable ammunition and 2) trigger time. And I don’t know about you, but I’m not going to pass those two up.
When was the last time you switched out your self-defense loads?