Depending on the level of accuracy you are going for with a rifle, the number of firings can make a difference. Probably NOT in an AR type rifle, but DEFINITELY in a high end target gun.

Many competitive rifle shooters will neck size only their fired brass (not necessarily true for semiauto rifles), and such cases will last nearly forever. There are very good reasons for that practice which I will not go into. For straight-wall handgun cases, they will survive large numbers of reloadings. I think I may still have some .38 Special brass that goes back to my earliest days of handloading in the mid-1960s. Back in my CAS days over 20 years ago, I used only .44 Mag and .44 Special cases, and I had only around 100 of each that I used only for CAS. And of course CAS loads are on the mild side. Those cases were probably reloaded at least 30-40 times each, on average, over about a 5 year period. I remember that I did lose some due to sidewall splits.