There's gotta be a million answers, but if you have to trim a lot, maybe look at the methods. If it were me, I'd probably load down a bit, and make sure it head spaces on the shoulder. Maybe, very little to no trimming will hold up longer. Maybe, anneal the the necks now and then and feel for how snug the primer pockets are. I wouldn't count on much case life with maximum magnum pressures and heavy resizing.