To save mulitple quoting, I concur what much of what's been said above.
You'll lose more .45ACP brass by sheer physical loss than by wearing it out.
If you reload it enough times, the mouth will split eventually, and you could prolly prevent this by annealing (which I've never done). BTW, if you spot a TINY split/crack in the crimp when inspecting your finished ammo, don't throw it away--go ahead and shoot it. (But that case won't be good to load again.)
Another possible cause of "wearing out" is the primer pocket getting too loose to safely hold a primer. (Pretty rare.)
I've never heard of a .45ACP case growing "too long" through repeated loading and shooting to be out of spec.
I have hundreds of .45 cases that have been shot so much that the headstamp has pretty much disappeared. And they're still good.
You can count on at least a half dozen loadings. And you wouldn't be out of line to expect twice that. :wink: