TrainingBy law anybody using a chainsaw must have had formal training. This law is largely ignored though but it does exist for a reason. Novice chainsaw users are those most at risk and if this law was ignored chainsaws accidents would be cut down to a fraction of the size.
Protective GlassesWhen using a chainsaws, debris can be shot off at over 30 mph and they may be sharp. Wearing protective eye wear is a must. Potential blindness is a factor that may be worth the tenner to eliminate.
HelmetMuch the same reason as the protective glasses but probably the most that will happen is a cut on your head. But more severe injuries have been known to occur so helmets are a big must when using a chainsaw.
Clothing & Gloves
Specialist chainsaw clothing can end up saving a limb and gloves a digit. As well as being resistant to a chainsaw the gloves also help with grip and friction allowing you to control the chainsaw more easily.