A lot will depend on the degree of maintenance the car has "enjoyed". Different systems require attention at different points in the time-line of a car's life. If you happen to acquire a car that will soon be needing major front end work, rotors/calipers, muffler system, etc., then you will be spending $$$$. Been there...done that.
When buying a used MB, "pedigree", i.e., service records, is very, very, important, unless you can DIY.