assessing used DSLR

(I sold the two D80's)

I need to put off the purchase of a D300 for six months to a year. Maybe
by then the price will be down around $1200-1400 USD for a new one.
Until that day, I plan to buy a used D200. In the first stages of
evaluating a used one, I'm thinking that a pro probably puts around 2k
clicks on a DSLR shutter per month---if more than that, they would
likely be using multiple cameras. More significant might be the number
of lens changes and the type of maintenance.

My experience with (film) cameras that are owned by a studio or a news
organization is that they get pretty good preventive maintenance and
even if the exteriors are rough the mechanical & electronic bits are
well-cared-for. How much of this do you guys think is applicable to
digital beasts?

If I'm on the wrong track someone please set me straight.
--
"It is the individual alone who is timeless. The individual's
hungers, anxieties, dreams, and preoccupations have remained
unchanged throughout the millennia." Eric Hoffer (1902-1983)