How efficiently do you think you work ? Do you think there's room for improvement? What things have you picked up allong the way that save that extra bending down, that extra few mins here and there? Kneeling down and realising you left your tape measure and pencil at the other side of the room. I think streamlining your work practices can have a big impact on what you achieve in a day and also how you feel at the end of the day! I was reading an article that was suggesting improving efficiency is actually more productive than working say an extra couple of hours at the end of the day when your tired.