Imagine you're running a Facebook ad campaign for a new coffee subscription service. For the first two weeks, your ad creative (a vibrant image of coffee beans with a catchy headline) performs exceptionally well: high CTR, low CPA. Your frequency is around 2.0. In the third week, you notice your frequency has climbed to 4.5, and simultaneously, your CTR has dropped by 30%, and your CPA has increased by 50%. This is a classic sign of ad creative fatigue. Your audience has seen the same ad too many times and is no longer responding to it.