I really try to do my maintenance on schedule but sometimes go over when I'm on the road. I do change oil when I know my coach is going to sit for awhile. My Workhorse manual says I should change oil and filter once a year / or every 7,500 miles whatever comes first. I'm a retired truckdriver and our shop changed oil in the diesel engines (which ran hard everyday) once every 20 thousand miles and the oil filters every 10 thousand miles. The trucks that had CAT diesel engines our shop ran those engines over full by one gallon by recommendation from NC Machinery.
