An ad unit’s automatic refresh rate determines how often a new ad request is generated for that ad unit.
We recommend using the Google-optimised automatic refresh rate. The optimised rate is calculated using AdMob historical data to ensure that the ads shown in your ad units are being refreshed at the best rate for banner ads.
You may also set a custom refresh rate of 30-120 seconds or disable refresh rate completely.
Refresh rate is disabled by default for native ads. Native ads should complement the content and environment surrounding them. Refreshing native ads regularly may interfere with the look, feel and cohesiveness of an app.