Once on a campaign overview you may notice the settings option which opens in a popup. One of the options in settings is called Frequency Cap. What does this do exactly? Frequency Cap is the amount of time until the popup will be shown again to one of your visitors. By default this is set to 1 Day (24 Hours), other options include 1 Hour (60 Minutes), 1 Week or 1 month.
To change the Frequency Cap, simply select an alternative from the drop down and click Save once you're finished with your changes