The way it was explained to me, the more headroom you have the better your amp will sound and the longer it will last. That being the word, I've always shot for plenty of power. I did a two guitar/singer and drummer rock band with 350 watts through a 410. I'm currently doing everything with a couple of 12/3 cabs and 500 watts. I mostly use a single cab with the same amp, but I've got the other cab if I need it and both of them together can't overwork the amp so it's all good (knock wood) in the hood.