Starting next week, the “rotate” setting for ad rotation will change. Instead of rotating creatives for an indefinite period of time, this setting will only rotate for a period of 30 days. After that, the setting will then optimize to show the ads expected to generate the most clicks. Every time a creative is enabled or edited, the ads in that ad group will rotate more evenly for a new period of 30 days.
Note that a campaign’s ‘Ad rotation’ setting will continue to say ‘Rotate evenly’ after the even rotation period has ended for any or all of the ad groups in the campaign.