I don't shoot my carry ammo once or twice a year because I am worried about it being too old to function. I do it to check the gun for problems with carry ammo.

My carry gun is a P365. When you push the limits on how small and light a 9mm can be it doesn't take much to make them unreliable. Recoil springs need to be changed more often, they wear more, magazines need stronger springs that may fatigue , etc. I want to check the gun/carry ammo combination on a regular basis.

My P365 had to go back to the factory because it started leaving empty casings in the chamber. This started after a few hundred rounds. The P365 has been reliable for the two years since then but while I trust it enough to carry it I don't trust it as much as I do my larger M&P Compact.

The Kahr PM9 I once had was much worse than the P365 about developing failures. The manual said it might have malfunctions during the first couple of hundred rounds but mine was 100% reliable for the first several hundred rounds. Then it started dropping mags, particularly with higher power ammo. Kahr sent me a metal mag catch to replace the plastic one and it quit dropping mags but a few hundred rounds later started getting stovepipes. Replacing the recoil spring seemed to fix that but I sold the gun before it found a new way to fail.

If I carried my M&P Compact, a Glock 19 or similar size gun I wouldn't check so often. But I end up always leaving guns that large at home.

I bought a half case of Gold Dot +P pre-Covid and am going to keep using it until I run out which may take several years. But I may buy some standard pressure carry ammo for the P365 and use the +P in my M&P Compact.