BEST ANSWER: If you are in fact a workaholic and you sense this company would like that: Say you are a confirmed workaholic, that you often work nights and weekends. Your family accepts this because it makes you fulfilled.
If you are not a workaholic: Say you have always worked hard and put in long hours. It goes with the territory. It one sense, it’s hard to keep track of the hours because your work is a labor of love, you enjoy nothing more than solving problems. So you’re almost always thinking about your work, including times when you’re home, while shaving in the morning, while commuting, etc.