How frequency works
Reach counts unique people. Impressions count total views. Frequency is the ratio between them, and it tells you whether you are reaching new people or re-showing the same faces. On a small audience, frequency climbs fast because there are only so many people to serve, so the platform recycles impressions against the same users. On a large audience it stays low for longer. This is why frequency and audience size are two views of the same problem, and why narrow retargeting pools fatigue first.
The fatigue curve
A small amount of repetition helps, because most people do not act on first exposure. Beyond a point, extra exposures stop persuading and start annoying, click-through rate falls, and Meta charges more to keep serving a stale ad. There is no universal cliff, but many advertisers watch for the range where cost per result begins climbing while reach flattens. Prospecting can tolerate lower frequency across a wide audience. Retargeting naturally runs higher because the pool is small and the intent is warmer.
Managing frequency in practice
The three levers are audience size, creative volume, and time. Widening the audience gives the algorithm more people to reach before it repeats. Rotating fresh creative resets attention even against the same audience, because a new ad is a new first impression. Frequency caps exist but are blunt, and on many objectives Meta manages delivery well enough that caps do more harm than good. The durable fix for fatigue is almost always more creative, not a harder cap.
How iClick uses frequency
iClick treats a rising frequency paired with a falling click-through rate as the earliest reliable signal that a Meta ad set needs new creative, usually before cost per result has moved enough to alarm a dashboard watcher. On tight retargeting audiences, higher frequency is expected and tolerated. On prospecting, a climbing frequency against a flat reach means the audience is too small for the budget, and the fix is a broader audience or a lookalike expansion rather than simply spending more into the same faces.
