Yup. Unfortunately, it's kind of like asking how many miles a motor should get. There are some semi-standards, but way too many variables for close figures. I have .38 brass that has been loaded literally dozens of times, and 06 brass pushing the dozen mark also. But on the opposite end of the spectrum, I loaded a wee bit heavy on the .243 once, and was able to push primers in by hand. Oops.The problem with giving a life span too is that many folks figure they are good up to that point and get lazy and only half-ass check their brass. Very bad habit! Especially with rifles. A much better question is "What flaws should I look for in my brass when reloading so I know when to toss it", because these flaws can rear their ugly head in a single shooting at times. So I would be more concerned with (loose) primer fit, cracked necks or shoulders, and severe rings or seperation at the base. I'm sure there are other things I am forgetting, but it's late, and I'm nursing a cold at the moment
. But hope that makes sense and helps a bit.