A few boxes to test the gun. But many hundreds of rounds in familiarization and practice. My G23 has never failed on me in many thousands of rounds (some is the gun some is the ammo... you never know when your going to get a bad round).
But this does not mean that I don't practice malfunction drills once in a while. There is no excuse for not doing this in your carry/defense firearm. Anything mechanical can fail no matter what is stamped on the receiver. My Glock, Hk, SIG, Beretta, etc can all fail. It is my job to be proficient with the platforms to ensure that a FTF or FTL is quickly remedied in the event it happens.
But this does not mean that I don't practice malfunction drills once in a while. There is no excuse for not doing this in your carry/defense firearm. Anything mechanical can fail no matter what is stamped on the receiver. My Glock, Hk, SIG, Beretta, etc can all fail. It is my job to be proficient with the platforms to ensure that a FTF or FTL is quickly remedied in the event it happens.