A basic spring service performed each year should include, at least, the following;
Sharpen or Replace and Adjust Chain (chainsaw) as needed.
Inspect air filter for dirt accumulation now, and before each usage and clean or replace. Replace air filter after 25 hours.
Inspect spark plug/s every 25 hours and replace if fouled.
Inspect entire unit including all wear items such as control cables, sprockets, handles, tubes and other parts and watch for worn, cracked, pinched or otherwise damaged parts, and replace if found.
Drain fuel-mix from fuel system and replace with fresh fuel-mix 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-mix with a fuel stabilizer)