RE: 30-06 brass life
Some lots of brass seem to be much softer than other lots, and this varies also from one make to another. For many years, Norma brass had a reputation for being soft compared to Remington and Winchester, and it would not permit loading to levels that the others would take.
Given brass of adequate temper and strength, case life is very dependent on the pressures to which it is loaded. I don't have a preference between Remington and Winchester like many people do, and I try to keep my loads to a level that will let me get as close to ten shots per batch of cases as I can with adequate accuracy, without giving up too much in the way of muzzle velocities.