There is a specific sentence in Costco's official membership policy that most members have never fully internalized — and that, once understood, changes the risk calculus of every membership decision the member will ever make: Costco offers a 100% satisfaction guarantee on membership itself. If you're not happy at any point — even years into your membership — you can cancel and receive a full refund of your membership fee. Full refund. Any time. No questions required. No pro-