thanks for joining the conversation, was your last public display of legal knowledge protesting your innocence just before taking a short vacation on her majesty's dime?
to be blunt if the case explodes or a squib and another right behind it and the gun blows up and injures the owner or user or spectator are you going to be their defence council or the expert witness,it is all fine and dandy until someone loses an eye,
a firearms instructor would be quite foolish to say cases can go 100 times because that is all most students will remember and not the caution to check cases and so on
a middle aged fellow who now builds gun barrels for a living had his reloads explode and destroy the gun at rocky range a couple of years ago, lucky no one was hurt, would the guy next to him have said, oh I will not sue as the cases would be good for 100 reloads or 30 for a rifle?
accidents do happen and people sue, careful with advice on gun nuts, the op said he is completely new to reloading, so complete proper advice is needed and that takes a page of notes and not some hot shot saying have at it,
the barrel builder will never shoot next to me, ever and if I see him at a range I will make it a point of asking how his ammo he is using was prepared,
and yes I would go so far if the answer was not satisfactory to tell the next person to get up off the bench until I explained his,past behaviour. Range bully, no just careful
have a nice day folks. Jeff
What a crock. Even if the number 4 did represent a threshold where the risk of case failure become greater (it doesn't), so what? Reloaded cases fail during firing every day, it's inconsequential. Case head separations are not common in pistol cases but even if they were they are harmless. Neck and body splits are a complete non-event.
Edit: I suppose if you are shooting one of these notorious unsupported chamber autos it could be an issue. Case head failures are disastrous. I've never loaded for one, but it shouldn't be an issue for anything outside of .40 cal.
To answer the question, low pressure pistol cases like the .45 auto and .38 special can be expected to survive at least 50 reloads if they are not pushed to excessive pressures, often they go over 100. Higher pressure cartridges like 9mm or .40 S&W will probably only last in the 20-50 reloads range (unless again you are dealing with a badly designed chamber).
The correct time to throw a case away is after it has failed. This means visible splits, loss of neck tension (to the point you can twist the bullet in the case after it has been fully seated) or primer pockets that are downright sloppy (does this happen in these calibers? I've never seen it). Fired so many times that the headstamp has worn off is not a good reason to throw pistol brass away, load those suckers up.