Recently I've had an interesting experience that reinforced and changed my practice of shooting carry ammo. Generally when I pick new carry ammo, I shoot about 250 rounds of it for figuring reliability and POA/POI. Subsequently, when I practice with my training ammo, I throw a round that was chambered during carry into mix to avoid re-chambering the same carry round twice.
I have a P7 that is coming up to 10K rounds, only stoppages I had were due to parts breakage. For some reason or another, I decided to go through a box of HSTs. To my annoyance, I had multiple failures to feed on last round it the mag - usually a sign of worn magazine spring. A slight increase in slide velocity with +P ammo over my regular training ammo was all that was needed to cause malfunctions. The theory was reinforced when gun went back to usual 100% reliability with all ammo after mag spring change.
Despite added expense, I'll be shooting my carry ammo more often and in slightly larger volumes.