A person's occupation is never a good barometer for assessing how a vehicle is cared for during a person's ownership...there are doctors who can afford a Maybach, but don't know which end of a dipstick to hold...and there are guys (and gals) who scrub floors for a living but manage to get a used MB and can tell you how to rebuild the motor bolt by bolt.
Of course, knowledge of the vehicle doesn't hold water either. If someone doesn't know much about cars follows the maintenance cycles by the book, they probably have a better car by far, than the shadetree mechanic who can overhaul an engine, but only changes the oil when it's empty.
Either way, let your trusted mechanic tell you what you're getting into...
PS I LOVE your quote on your signature...and THAT'S no joke! (mind if our pastor uses it?)
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car