Affiliate marketers obsess over commission rates and barely glance at cookie windows. That's backwards for anything with a considered purchase, because the window determines whether you get paid at all.
The mechanic
Someone clicks your affiliate link. The network sets a cookie in their browser recording that you referred them. If they buy within the cookie window, the sale is attributed to you and you earn the commission.
Click, cookie, purchase, attribution. That's the whole system.
If they buy after the window expires, you earn nothing — even though your article is the reason they knew the product existed.
Why the window matters so much
Purchase timelines vary enormously by category:
| Product type | Typical decision time | |---|---| | Impulse consumer goods | Same session | | Consumer subscription (streaming, VPN) | 1–7 days | | Mid-market SaaS | 2–6 weeks | | Enterprise software | 1–6 months | | Financial products | 2–8 weeks | | Mattresses, furniture | 2–12 weeks |
Now compare that with a 30-day cookie. For a VPN, 30 days is plenty. For enterprise software with a procurement process, 30 days is close to worthless — the buyer will still be in evaluation when your attribution expires.
This is why a 90-day cookie at a lower rate frequently beats a 30-day cookie at a higher one. The higher rate only pays on sales you actually get credit for.
Where attribution quietly breaks
Cookie windows are the advertised limit. Several things shorten it in practice, and none of them are disclosed on the program page.
Safari and Firefox cap cookie lifetimes. Safari's Intelligent Tracking Prevention limits client-side cookies to seven days, and in some cases 24 hours, regardless of the advertised window. Firefox's Total Cookie Protection behaves similarly. If a meaningful share of your audience is on iPhone — and for consumer topics it will be — your effective window on that traffic is a week, not ninety days.
Ad blockers block the tracking call. A click that never registers can never convert.
Cross-device journeys lose the trail. Someone reads your review on a phone and buys on a laptop. Same person, different browser, no cookie. Unless the network does authenticated cross-device tracking, that sale is invisible to you.
Last-click attribution overwrites you. Most programs pay the last affiliate link clicked. If your reader later clicks a coupon site's link before checkout, that site takes the commission. This is why coupon and cashback sites earn so much on other people's content, and it's the single most common way affiliate income disappears.
Direct navigation breaks it entirely. The reader remembers the brand, types it into their browser a week later, and buys. No affiliate involved.
The realistic conclusion: your effective attribution rate is meaningfully below what the advertised window implies. Plan for it rather than being surprised by it.
What to look for in a program
- Window relative to the decision cycle. Match the window to how long the purchase actually takes, not to what sounds generous.
- Whether the cookie refreshes on a new click. Some programs reset the clock each time; others count from first touch only.
- First-click vs last-click. First-click attribution is rare and hugely valuable to content sites. It's almost always worth asking.
- Whether coupon and cashback partners are allowed. If they are, expect to lose some share of sales at the last step.
- Return and refund windows. A commission can be clawed back after a refund, so a long return policy adds risk after the sale.
Practical implications for your content
Write for the moment of decision. Content that catches someone early in research relies on a long window to pay out. Content that catches them at the point of purchase — comparisons, "best X for Y", pricing breakdowns — converts inside almost any window.
Prefer recurring commissions where the window is short. If you only get credit for the first payment, a subscription with recurring commissions keeps paying long after the cookie has expired.
Don't chase the highest rate blindly. Run the arithmetic: rate × the share of sales you'll actually be credited for. A 20% commission with a 120-day window and first-click attribution will usually beat 40% with 24 hours and last-click.
You can compare cookie windows across the full directory, which lists them alongside commission rates for every program — but always confirm the current terms with the program itself, since these change without notice.