Just another reason to inspect your weapons every time you clean them. For a carry gun, might not be a bad idea to do that once a week.
I would not give up on Glock. They have too good a track record for this to mean anything other than.. any gun can fail. They are imperfect manufactured devices, designed by imperfect people using imperfect materials and imperfect measuring methods.
Blasphemy! Glocks are perfect and do not fail the OP was clearly doing something wrong!
This entire thread reminds of a sign I once saw. It said "Clock repair" but looked like "Glock repair", which prompted me to think "Wow, how has he managed to stay in business?".
Anyways, there is no real amount. I try to shoot my carry guns at least once every other week, and at least 100 rounds of my carry ammo. I dont stress out about performance figures on ammo, and would rather carry something that I am familiar with and have practiced with, but that is just my . I inspect any gun I am going to carry weekly, and if I have any issue I wont carry it until my confidence is restored in it.