Frequency

Frequency is the average number of times a unique person saw a given ad over a period, calculated as impressions divided by reach.

Frequency has a sweet spot that depends on the campaign objective and creative quality. Too low, and the message doesn't register. Too high, and you get ad fatigue — declining CTR, rising negative feedback, and wasted spend on people who've already made up their mind. Retargeting campaigns typically tolerate (and need) higher frequency than cold-audience prospecting.

Frequency caps (a platform setting that limits how many times one person sees an ad in a given window) are the direct control lever for managing this, and most performance teams tighten the cap as a campaign matures and creative starts to wear out.