Meta retargeting window for slow-decision services: 7 days or 30?

Take a dental clinic running Meta retargeting on the default 7-day site visitor window, which most people never touch. Someone reads the whitening page on Monday and books the following Sunday, after talking it over at home. A 7-day window never reaches them, and the audience usually ends up too small to deliver anyway.

My view is to go 30 days for anything where the decision takes more than a week, and split it: a short window for people who hit the booking page, and a long one for general site traffic. The catch is that 30 days also sweeps in people who already booked, so exclude recent patients or you'll pay to remind them of an appointment they already have.

Mira, I don't think "audience too small" is the real issue. A 7-day window is usually fine for volume on Meta. The bigger problem with 30 days is that frequency stretches over a long window, so the same people end up seeing the same whitening ad for weeks. Your split deals with that. Still, I'd cap frequency on the long audience before assuming the longer window is the fix.

Fair point on frequency, but it really comes down to how many people hit the site each month. If a clinic gets a few thousand unique visitors a month, a 30-day general audience is already big enough that frequency stays low, so the cap matters less than people think. If traffic is thin, the cap is what actually matters.

Iris, I'm not sure the volume holds up. A few thousand uniques sounds big, but most of them are one-time visitors who read a page and left, and a whitening ad can't do much with them. The ones it can work on are the repeat visitors, and in a 30-day window that's often only a few hundred people. Put a normal daily budget against that and frequency climbs fast, whatever the total traffic number says. So size the audience by how many people came back, not how many came in.

Meta won't give you a repeat visitor count directly. The website audience builder can't filter by visit count as far as I know, so "came back" isn't a rule you can click. The closest proxy is a page-based audience: people who viewed the whitening page or the pricing page are the ones actually comparing options. Build the 30-day audience on that, then check its size in Ads Manager before you set a budget.

That also bears on Theo's point. In standard ad sets you don't get a hard frequency cap. Frequency is just what you end up with, based on audience size, budget and exclusions. A true cap belongs to reach and frequency buying, which is a different setup. So for a clinic, the practical fix is usually a narrower audience on a lower budget, not a bigger audience with a cap bolted on.

Agreed on the cap. Meta's standard ad sets don't give you one, so frequency is really a side effect of audience size and budget, and those are the levers you actually have. One thing nobody's mentioned is audience expansion. If it's switched on in the ad set, Meta can quietly widen past your 30-day page audience and pull in people who never touched the whitening page. That makes the frequency numbers look fine while the reach drifts. Turn it off for the retargeting ad set and the audience stays the size you built.

Then look at frequency over a 7-day window, not the lifetime number. For a clinic, I'd start getting nervous once the same audience sees the ad more than 3 times in a week, and if the audience is only a few hundred people, you'll hit that fast. The fix is usually a smaller daily budget, not a bigger audience.