Not very often, I suspect.
From an owner's point of view,running an agency this way means you don't have to as much compared to running one for mere mortals. Getting say a third of 'a lot' may not happen very often, but that's ok.
From the staff's point of view, getting say two thirds of 'a lot' is going to happen far less frequently, and that's less ok, particularly as they don't want you working anywhere else.