I bought my Norma brass like 2 years ago. All cases are still in use. Some have 6 or 7 loads through them. Haven't lost one (to failure, impending failure) yet.
In my last benchrest rifle, I used Lapua .220 Russian brass necked up and fire formed to 6PPC. I'd do full prep on 30-40 cases... and those would be the cases I'd use for the entire life of a particular barrel.
Of those 30-40, 20 or so would be record cases and the balance sighters and back-ups.
The "perfect 20" would get used about 75 to 100 times a season. Just enough neck sizing to get about 5 lbs of seating pressure... and shoulder bumped about .0015" every 5-10 loadings, depending on temps and... bla bla bla.
OCD is us...