When I get there we dig in. We'll work 2 hours then take a little break. Have a snack ready for yourself (I'll bring mine) for fortification! Then we work 2 more hours. You can be hands on or I can do all the running around.
Part of my service is to remove anything that I have a resource for (and will fit in my van). I don't take garbage or recycling. If I'm taking things away, I'll leave 15 minutes to a half hour before the end of the session.
If the nature of the project would benefit from additional people, depending on availability, I will bring another set of hands. The pricing for any additional people will depend on their experience and will be ok'd by you ahead of time.
I'm a green business and will separate garbage/recycling/compost/ donations at each session.