Most ad platforms default retargeting audiences to a 7-day window. If your typical buyer takes longer than that to convert, you drop them from the pool before they act — then pay full acquisition cost to win them back. Match window length to your real days-to-conversion data, not the default.
- A 7-day retargeting window misses everyone whose real buying cycle is longer — they don't vanish, they just convert without ever seeing your ad again.
- Platform defaults are built for a fresh, cheap audience, not your actual sales cycle — nobody sizes this to real data unless you tell them to.
- Pull your own days-to-conversion distribution from GA4 or your CRM before deciding how long a window you actually need.
- Segment by recency instead of one blanket audience — a lead from day 2 and a lead from day 25 need different creative and different bids.
Check your Meta or Google Ads retargeting audience settings right now. There's a decent chance the membership window is set to 7 days — either because that's the default, or because someone set it low months ago to keep the audience "fresh" and cheap, and nobody's touched it since. Every visitor who takes longer than a week to come back and buy has already dropped out of that pool by the time they're actually ready.
Why the window shrank without anyone deciding it should
Nobody sat down and chose 7 days. It's what's left after a handful of separate decisions stacked up: iOS's App Tracking Transparency prompt cut off a lot of the device-level signal platforms used to build longer-lived audiences; Meta's own default attribution window (a 7-day click, 1-day view) shapes how a lot of advertisers think about "how long someone stays relevant" even though attribution and audience membership are two different settings; and shorter windows just look better on a dashboard — a smaller, more recently-active audience is cheaper to serve and reports a tighter cost per conversion, so accounts drift toward trimming duration rather than extending it.
None of that has anything to do with how long your buyers actually take to decide.
The math you're not running
This is the test that actually matters, and it's one most accounts never run: pull your own days-to-conversion distribution — first touch to purchase — out of GA4 or your CRM, and lay it against your current retargeting window. Whatever share of your eventual buyers converts after that window closes is money you're spending twice: once to bring them in the first time, and again to reacquire them cold once they've aged out of the retargeting pool, because by then they look like a brand-new visitor to the algorithm.
For a business with a short, impulse-driven purchase, 7 days might genuinely cover most of it. For anything with real consideration — higher price points, a multi-person decision, a service they're comparing against alternatives — a big share of buyers are still deciding well past day 7, and every one of them is currently invisible to your retargeting campaigns.
What to actually do about it
Set custom audience durations off your own data, not the platform default — if your median days-to-conversion is 18, a 7-day window was never going to catch the middle of your funnel, let alone the tail. Then stop treating the audience as one block: layer it by recency instead, with different creative and bids for 0–7 days (still warm, keep it simple) versus 8–21+ days (they need a reason to come back, not just a reminder you exist). Revisit the distribution every quarter — pricing changes, seasonality and even your own ad frequency can shift how long people actually take.
The fix costs nothing to test. It just requires checking a number most accounts have never pulled.
Related reading: we've written before about how Meta and GA4 already measure conversion windows differently — worth understanding before you start resizing audiences around either platform's numbers.
Related service: Performance Marketing