Things get murky because you have to include commuting and preparation/returning home time. But I also like to distinguish physical time and mental time. Sure physically I'm at work for 40 hours a week, but the mental space it takes up is far more.

If anyone has good tips on how to mentally separate from work after hours I would love to hear them. I know some people can literally switch it on and off like a light but I've never been able to.