In my mid 20's I did no cardio at all unless it was for fat loss, no emphasis on fitness whatsoever. Now that I'm older I try to keep a better overall fitness level and spend just as much time outside the gym working on cardio as I do in the gym. My 'live fast and leave a good looking corpse' philosophy seems to be wearing off the older I get.

Plus, at least to me, the better my cardio is, the more wind I have in the gym, the better my weightlifting goes. But also I'm one of those people who could gain weight drinking water so I have to keep an eye on myself when I lift as even things like low-carb protein shakes can put fat on me. I will never be the guy who eats only boiled egg whites and broccoli so cardio is just part of the lifestyle whether I like it or not.