What do you consider low/high hours on a camera?
 

Just a poll to see what you consider low hours vs. medium vs. high hours on a video camera.

For example:
Low under 50, medium 100, high over 200

Sony suggest replacing the heads on a DSR 300 after 1,500 hours. So I would suggest under 500 hours low, 500 - 1000 average, and over 1000, high.

While we're on the subject, someone told me that the camera heads are rolling while the camera is turned on even if your not actually shooting anything.
True or false?