I guess it depends on what you find fulfilling. Having new and interesting experiences in your 20s and 30s can have a pretty different effect on your life than leasure time in your 40s+. In my experience there is minimal overlap between people who maximized working hours in their younger years and have an exciting life outside of work later on. But I'm sure that's partly a reflection on my social circle and everyone is different; there's no one-size-fits-all life advice.