A basic spring service performed each year should include, at least, the following;
Check the Oil and inspect for contaminants such as water (milky), fuel (too full, thin and smells of gas) or metal particles. Contact a service tech if any are found.
Change your oil now and every 25 hours thereafter.
Sharpen blades now and every 25 hours thereafter.
Inspect air filters for dirt accumulation now, and before each usage and clean or replace. Replace air filters after 25 hours.
Inspect spark plugs every 25 hours and replace if fouled.
Grease all bearings and mechanisms requiring grease.
Inspect entire unit including all wear items such as belts, tires, control cables, bearings and other parts and watch for worn, cracked, pinched or otherwise damaged parts, and replace if found.
Drain fuel from fuel system and replace with fresh fuel if it has been over three months since last usage without fuel stabilizer. If performing and end-of-season service, drain fuel tank or run engine until it runs out of fuel. (alternatively you may dose "fresh" fuel with a fuel stabilizer)