A great friend once (last September) said to me (about work/life balance), "Look, it's just math. You only have a certain amount of hours a day to do what you want and need to do. You have to make sure what you're doing is worth your time."
I'm sure she doesn't even remember telling me this, but I did go home, and i did do the math (broken down by day and by hour, organized by category):
then a week later, I started factoring my equations.