Hours on the XF300
 

I was just wondering what these cameras are rated for. I looked at canon and I didn't expect they would give a hour rating. But what could one expect to get out of these cameras before something might need replacing. What is a typical life in hours. This is useful in determining how much you shoot vs.how much your getting paid. For example I shoot some corporate meetings and the camera could be on for over 4 hours. If I make $500 I could figure my camera replacement cost in the equation.
Also what might be the wear item with these cameras since there isn't a play head and tape mechanism that was typically the wear items in the tape based cameras.
thanks

scott