Ad Rotation enables you to rotate ads within an ad set automatically. Use this feature to reduce ad fatigue and serve your audience with fresh ads with less manual work.
A rotation rule can be defined based on the number of days the ad has been running, by frequency, or by a performance metric such as CPA. Frequency refers to how many times an ad has been shown, on average, to each individual user. After all ads in the ad set have been rotated, you can select whether ad rotation starts a new rotation from the beginning, leaves the last ad running, or pauses all ads.
To keep showing ads after all the ads have been rotated, select the keep last ones running option. This ensures that the campaign doesn't stop when you have no more fresh ads to show.
Note It's not recommended to use ad rotation in combination with the Automated Ads "feed based status" feature. They don't work well together and the results may be unpredicatble.
Ad rotation order
When ad rotation is enabled the first time, the ads are rotated in the order they were set in Campaign creation wizard. A will go first, then B, etc.
When all ads have been rotated, Ad Rotation next picks the ads that have been paused for the longest time.