Triggers / Repeat Control
If Repeat popup is turned off then the popup will appear only once, except your visitor is using another browser or Private / Incognito mode.
When it's turned on you can define in the Repeat after option the number of days, after you want to repeat the popup. 0 days means the end of the browser session. Empty value means that it can be triggered after every page load, this option isn't recommanded when Open automatically after x seconds is active.
If you turn on the Prevent reopening option, then after the popup was opened, no more triggers can open it again. It's very useful in conbination with Open at scroll position. Make sure that this option should be turned off when you have an active Open by click trigger.