What is Creative fatigue?
Creative fatigue is the decline in an ad's results as the same people see it again and again: click-through rate falls and costs rise while frequency climbs.
Fatigue is gradual, which is why it's easy to miss. The usual signals are falling CTR, rising frequency and a rising cost per purchase on an ad that used to work.
The fix is fresh creative: a new hook, format or angle, or a broader audience so the ad reaches people who haven't seen it.
Example
An ad's CTR falls 38% over nine days while its frequency rises from 1.8 to 4.7.