When playing golf, categorize each of the following items as "useful" or "useless": Irons, putter, dumbbell, tees, skis, range finder, jeans, kayak.

Irons: Useful
Putter: Useful
Dumbbell: Useless
Tees: Useful
Skis: Useless
Range Finder: Useful
Jeans: Useless
Kayak: Useless