The short answer
Three settings do most of the work: a frequency cap so nobody sees the ad constantly, an exclusion list so customers stop seeing acquisition ads, and a membership window that matches how long people actually take to decide.
Defaults on all three are usually wrong for a considered services purchase.
Exclusions first
- People who already submitted an enquiry
- Existing customers, unless the campaign is for them
- People who visited only your careers or support pages
- Anyone who has seen the campaign many times without acting
The first is the one that embarrasses businesses most often. Continuing to advertise at someone who enquired last week suggests nobody is paying attention, and they notice.
Match the window to the cycle
| Purchase type | Sensible window |
|---|---|
| Impulse or low value | Days |
| Considered consumer purchase | Weeks |
| B2B services | Weeks to a few months |
| Long procurement | Months, with low frequency |
A thirty-day default on a purchase that takes three months stops just as people are deciding. A long window at high frequency is the other failure.
Segment by what they did
Someone who read one page and left is not the same prospect as someone who spent ten minutes on your pricing page. Treating them identically wastes spend on the first and under-serves the second.
Build audiences from behaviour that indicates interest, and show them something that moves them forward rather than the same advertisement again.
Respect the obvious
Retargeting is visible to the person being retargeted in a way most advertising is not. Frequency that feels attentive at three impressions feels intrusive at thirty.
Cap it, rotate creative so it is not identical every time, and give people a straightforward path to the thing they were looking at rather than to your home page.