I guess it just boils down to what you want to do with your spare time. You find time for HN. Me, I can find time for 20-60 min a day studying Japanese (of which 5-20 is in Anki). I also find time for 20-60 min a day playing go so ¯\_(ツ)_/¯
Fine, time AND energy. HN is entertainment. SR feels like work. When I have an hour at night on average to yourself, I don't want to spend it studying. I've tried taking breaks at work to do it, but you need those mini breaks at work to be a bit unproductive as well. I can't be "ON" 100% of the time, I need rest.
