Cookie duration is the time period an affiliate gets credit for a sale after someone clicks their link. Some programs give 24 hours, others give 30 days, and some even give lifetime cookies. The longer the cookie, the better chance the affiliate has to earn commission even if the person does not buy right away. People often need time to think before buying, so short cookies can mean lost earnings. But programs with longer cookies sometimes pay lower commission rates. This creates a choice between cookie length and payment amount. Which one matters more when picking programs to promote?