I know that the shutter could fail on one of my first images, or it could keep going strong hundreds of thousands more, and that a typical Nikon shutter replacement runs anywhere from $250-400 USD.
From what I understand, shutter actuation counts are mostly intended to be used to loosely gauge the probability of an impeding shutter's failure. Many photographers here and elsewhere on the Internet seem to treat shutter failure as camera failure.
My questions are:
Are shutter actuation counts useful for determining the the probability of failure of other components, like the system board, image sensor, flash, card reader, LCD?
With a camera with a high number of shutter actuations, what can and should be done maintenance-wise (professionally or DIY) to extend the lifetime of the camera as a whole?