I've never considered for a moment of doing a 20min oil (only) change. Our logbook entries for an oil change always include a full firewall forward inspection. My "condition inspection" happens every 25-30hrs. Don't worry, many of us don't need the reminder to get off our lazy butt to maintain a half way decent airplane.
by Card Machine Works
RV-9A N4822C flying 2200+hrs. / Cedar Park, TX
RV8 Building - fuselage / showplanes canopy (Done!)