Every 100 hours of use or once yearly these services are recommended by the manufacture:
Change engine oil & filter. Visually inspect thermostat for corrosion. Check low-pressure fuel filter. Check mounting and alignment hardware. Check the corrosion control anodes. Drain and replace gear case oil. Inspect battery. Check wiring and connectors. Check cowl seals. Check internal cowl and sounds reduction foam. Check intake silencer. Check idea relief muffler.