Using ad rotation and frequency capping
Ad rotation is the way that we deliver your ads on both the Search Network and the Display Network. If you have multiple ads within an ad group, your ads will rotate because no more than one ad from your account can be shown at a time.
Use the ad rotation setting, available for campaigns with 'All features' enabled, to specify how often you'd like the ads in your ad group to be served in relation to each other. (Note: Ad rotation settings aren't available for Smart Display campaigns.)
There are two options for ad rotation: optimise and rotate indefinitely.
This setting will optimise your ads for clicks in each individual auction using signals like keyword, search term, device, location and more. Powered by Google’s machine learning technology, the optimise setting prioritises ads that are expected to perform better than other ads within an ad group.
If you'd like to prioritise conversions, use Smart Bidding, which will tailor your bids based on the likelihood of a conversion, and choose the ad most likely to drive that conversion. If you’re using Smart Bidding, AdWords will automatically use the optimise ad rotation setting.
This option delivers your ads more evenly into the ad auction for an indefinite amount of time and doesn’t optimise. This option isn’t recommended for most advertisers.
Bear in mind
With the rotate indefinitely option, the percentage of impressions for ads served in the ad group will be more even than the optimise ad rotation option. However, because the quality of the ads differ, and quality is used to determine where an ad appears, or if it even appears at all, the percentage of impressions for each ad may not be perfectly even.
An ad with high quality may appear on the first page of search results, whilst an ad with low quality may show on the second page of search results, reaching a smaller number of users.
How to change ad rotation and frequency capping
Select the AdWords experience that you're using. Learn more