Back when I was competing in and practicing for IPSC and IDPA, there were a few years that I shot upwards of 30,000 times per year. I never had more than 500 rounds of 45 acp brass dedicated to this effort. I reloaded cases until they split. Many cases went into the 30 count and a few went into 40 times. Mind you these loads were all loaded to make the 'major' category in muzzle energy. I was using a taper crimp and loading with RCBS carbide die on a Dillon 550. When 10 or 20 cases were split and tossed I would add that same amount of new cases to the lot. There was a definite difference in longevity with regard to the manufacturer. I had my best performance with Winchester Western and Remington brands. Up to about the number 10 I could count the number of times a brass had been fired by counting the imprints of the Colt M 1911 ejector rod on the rim of the case. After that it became too obliterated to read much of anything. I used WW and Rem. primers thru that time and never had one slam fire. But I kept on top of my M 1911 maintenance and always had strong firing pin springs installed.

An aside; I saw two 45 acp barrels break off at the first locking lug and spit out on the ground during competition. I saw several frames that cracked usually at the opening for the slide stop. I saw one slide break at the ejection port opening. I saw many extractors and ejectors break. Front sights were always disappearing. Most all those problems were solved within a few years after USPSA/IPSA competition began.

My last two years of competition I used .38 Supers. That brass lasted about 1/2 to 2/3rds as long as 45 acp did on the average. And the locking lug area of the 38 Super barrels showed considerable more battering than the 45 acps did.