When I have used my D800 for the "Time Lapse photography" function, the camera shoots individual frames with the shutter and mirror operating each cycle. Apparently the camera is shooting a raw and processing it into a 1080(or 720) line video frame at each exposure, then assembling these video frames into a video file at the end.
When using the Interval Timer function, the shutter/mirror cycling is the same.
When you shoot regular 24/25/30/50/60 FPS video, the shutter/mirror stays open for the length of the shot.
Conceivably, the heat generated during a long video take could be considered "wear and tear", but that's for someone else to answer.