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I don't pick up range brass because I don't know where it's been. ...
I agree that can be a problem. There are times though, when the boxes in the trash bins match the shiny brass on the ground. Last trip I picked up a lot of .50AE, and some .270 Win, another time a bunch of .375 H&H. Don't own any of them, but maybe someday...
In any case, every piece I keep gets a cursory inspection, tumbled clean, then a more thorough inspection when I pop the primers and resize, including a feeler gauge inspection for impending case-head separation.
As to the number of times I reload a particular piece of brass, it depends on the cartridge, loads and rifle. I had a Rem M700 in .308 Win that did was very hard on full-length resized brass - as few as 3 firings and case-head separations occurred. Sold the rifle, even though it was a tack driver.
My 7mm RM used to have problems after 4-5 firings. After I decreased the powder charge things were OK. There is something in the chamber that leaves tiny scratch marks on the extracted cases, making it possible to count the number of times a case has been chambered. Since changing the load I have gone as high as 18 firings per case, although I generally scrap the cases before then.
I know one guy that was claimed to be getting close to 50 firings from his .45-70 brass. Too many for me, but I'm past 10 on some of my brass.
