Affiliate Cookie, Affiliate Cookie Length

An affiliate cookie is a small piece of code that is embedded on the user’s computer when they click on an affiliate link. The cookie enables sales tracking and confirmation that an affiliate should be paid for a sale. Cookies last for a specific period of time and affiliates get paid for sales made to users during that time period. Cookies are used to track sales to the original affiliate because users sometimes visit other sites before returning to make a purchase. Affiliates like affiliate cookie durations to be as long as possible. I recommend researching your competitor’s cookie durations before determining your own. Some merchants offer longer cookie durations rather than higher commissions to compete.
• Cookie duration
Cookie duration is an emotional issue with affiliates. Unless critical to the client business model or restricted via the affiliate network,Irecommend a 90 or 365 day cookie.
• Cookie occurrences
This details how many occurrences the cookie will be valid for. I recommend unlimited- other options usually breed bad publicity for little gain, and this also acts as a barrier to recruiting new affiliates.

See
Affiliate Marketing for Merchants
Affiliate Marketing for Merchants
Affiliate Book Affiliate Handbook