How Soon Do Affiliate Cookies Expire?

"How do affiliate programs work when the person I refer doesn't buy on the first visit, but on a subsequent visit? Will I still get credit for the sale?" -- Allan Nichols

The typical affiliate program works this way: When someone clicks an affiliate link on your website, he is taken to the merchant's site and a cookie, which identifies your site as the source of the visit, is put on his web browser. That cookie may expire in 30, 60, or 90 days -- sometimes less. In the case of Amazon.com, the referral is only good if a purchase is made during the same visit. The other variable is whether another affiliate's cookie can replace yours before the sale is made. Usually (but not always), the first affiliate to send a customer to a site gets the commission. To know for sure, check the merchant's policy in the terms of the affiliate agreement or e-mail and ask.

Wise merchants set up their affiliate policies to benefit their affiliates -- not to avoid paying them. They know that paid affiliates are motivated to send them referrals in the future.

http://www.wilsonweb.com/art/ads/cookies-expire.htm