Consider it as a whole. Rather than thinking of your work and life day to day, think of it as a whole. How many times did you get away with your family last year? Were there particular weeks/months when you worked really, really long hours? Were there times you were less busy? You might find that, when viewed that way, you did have a balanced life. Or you might realize you need to make a change in the way you do things during the upcoming year.
It is going to be virtually impossible to achieve complete balance every day of your life. There will simply be days and weeks when your work requires more time from you. There will also be days when your family requires more of your time. Instead of driving yourself crazy trying to achieve a work/life balance every day, look at your life on a weekly, monthly, and yearly basis. Schedule times to work hard, recharge, renew, play, and engage with your family and friends.