Join Date: Aug 2015
Location: Pittsfield, NH, USA
Giving the model and year might help you get meaningful results for your situation.
My wife has a 1995 M900, with (we think) about 25K miles on it. The valves, seats, and heads are original. The valve guides needed replacement.
I have a 1993 M900, with 260K miles on it. I have replaced the rubber seals on the valve guides a few times, but it is otherwise all original parts.
1993 Ducati Monster M900, bought new, 265K miles, killed by minivan 30Oct17. 1995 M900, was ex-wife's bike, now mine again.