One of the first things a new affiliate programme will encounter is the question of cookie life. Most affiliate programmes offer a 30 to 90 day cookie.
An affiliate cookie is used when a user visits a merchant's website; a small text file (the cookie) is automatically placed on their browser which enables the affiliate network to track the time stamp when the person clicks on the affiliate link. Once the cookie is set, the user can leave the site and come back another day (even if they don't use the same affiliate url). As long as the user makes a purchase before the cookie expires, affiliates will get their cut of the sale.
The life span of an affiliate cookie is set from the time that the user clicks on an affiliate link and it will end on the day that the merchant decides that they do not wish to pay the affiliate their commission on the orders placed by the referred customer.
Some brands will set their cookie life at just 24 hours; however we would not recommend this, as a short cookie period is not attractive for affiliates as it looks like the merchant is trying to skim the commission that the affiliate could have earned from referring the user. The vast majority of affiliate generated sales happen in the first 2 days of the original click. Many merchants set their affiliate cookie to coincide with their returns policy - e.g. 28 days return period, 30 day cookie. However there is no scientific reason to doing this, so we would recommend clients increase their cookie period for as long as possible. This tells affiliates that you are an affiliate friendly programme and they will see it as a bonus for their activity.