My work day when in the field has pretty much been start at 9 and pick up at 3. No breaks, no lunch (I eat snacks on the fly). I figure that's anyone's 8 hour day when you include breaks and non-productive time and most likely better than that in a lot of circumstances. In general, that makes about an 8 hour day with driving included.
If I worked for a another contractor out of his shop in his truck, it would be about the same. Yet, I see a lot of those guys goofing off, so I don't know how some contractors that supply the truck make any money. And I work faster than most, or so I'm told. I'm only charging for the 6 hours, so I'm screwing myself. Many of my customers don't even pick up on the deal they're getting if I'm hourly.
But, it's all over now because of the lack of work. So, I sit here and play when I should be making some molds for parts. At home I have so little time management skills it would pay for me to take any work with me and go to someone's else house.