I shoot pistol brass until it splits.
Some is all the same head stamp because I bought it, such as .32 Long and .32 Mag, others are mixed, such as .45 Colt, and some like 9MM, are a horrid mix of range brass, despite the fact I have enough to sort out a bunch all the same headstamp.
I shoot rifle brass until the neck splits, the primer pocket gets loose, or it shows
signs of an internal rut.
My match brass for .308 is all Lapua all the same lot, shot the same number of times and fully prepped.
My .223 blasting/plinking ammo is mixed range brass. I have a batch of 500 all the same headstamp .223 brass, but it doesn't shoot all that much better than mixed and I am not shooting matches with it anyway, just having fun.
Much of my other rifle brass is all the same headstamp. I don't do anything special to prep it, just trim, chamfer, deburr, and clean the primer pockets.