I guess I like to walk on the ragged edge, using some of the old stuff but there can be a down side.
A particular lot of pre-war Franfort Arsenal ('33 I believe) was known to be possessing of soft case heads. Can you say blow up?!
Some wartime '06 brass was less than high quality too though I've used lots of it over the years and still have some that is available to load. I have a friend that had a factory WWII production Frankfort Arsenal cartridge that let go because of a soft case head and wrecked a complete and original M1. Well, the stock anyway. Blew the side out of it when the M1's excellent gas handling system vented into the clip well. The primer went to the "unknown zone" and the case was cracked from the flash hole, through the case head and up the case side about half way to the shoulder. Was ugly. Both of us were unhurt though I was sprayed with splinters because I was standing eighteen inches to his left and looking at the rifle when it happened. I was wearing shooting glasses. The incident was quite spectacular.
The low pressure .38 Special, .45 ACP, and other cartridge cases I've used from ancient times just generally fade away with mouth cracks. A bit more care might be taken with high pressure rounds, especially if the cases could be weakened by early priming compounds.
My early .405 cases have a few loadings under their belts and were manufactured after noncorrosive priming compounds were introduced. Still, I hold them in reserve or else use them for mild powder puff loads using .41 Magnum pistol bullets. They've been handloaded with full power loads but might be getting brittle. They could be annealed but that's a lot of bother for uneven results. I used them back before the return of newly made .405 brass.
"I have cases I've been reloading since 1977 that have been hit by the ejector of a 1911 so many times that you can no longer read the headstamp!"
I started loading .45 ACP in 1978 and have cases like that that are still going strong. No way to know how many times they've been loaded. I still recognize some of the headstamps of old cases I've been using since that time.