Depending on use its good to carry a spare new plug for all the small gas powerd equipment, sometimes they get carbon fould from funky gas and they load up, the best thing for chainsaws and lawn mowers and small gas generators is a new sparkplug and fresh gas.
I go through several sets of sparkplugs on snowmobiles, and seems some brands of engines run better with certain brands/types of sparkplugs and sparkplug caps.
I know My 1994 Arctic cat does not run well with Champion Sparkplugs or Bosh, NGK for the snowmobile. the 4 cycle motors may do better with Irridum plugs.
I had just helpd a boat owner change his first set of sparkplugs on his 2008 Phantom Sport jets boat (Merc 200) half the sparkplugs had the electrode ceramic cracked off that had been in that motor for 2 seasons, check your sparkplugs and use antisieze when reinstalling.