I always anneal before sizing. Do it on the theory that heat and the annealing process will slightly distort the brass. Sizing straightens the minuscule distortion. I load for hunting. I require accuracy and velocity so many of my loads are at max recommended. In most I average about 10-12 reloads before I have to dump the brass. I do have one batch of 30-06 brass that I kept firing just to see how many I could get before cracks and case separation and I got up into the high 40's but you could definitely feel the impending case separation.
