With display frequency settings you can set how much time you would like it to take before the same form will be shown to the same visitor again. You can determine the period of time in days.
Thus, if you set it to 7 days, and the visitor visits your site every they, the form will appear to him or her only once a week.
"Day zero" is therefore not steady, but it depends on the first visit of the user, not influencing how other visitors will see the site.
Similarly to trigger settings, you can find display frequency settings on the individual pages of each types of forms. Note that display frequency can't be set for every type of form:
Display frequency settings can be found by clicking on the blue text under "Display Frequency" the text is "All the time" in this example):
The settings will open up in a new window which looks like this:
If the number is set to zero, the form will be displayed every time the visitor comes to the site.
You can change the number of days with the moving the slider (indicated by the first arrow) or by typing a number into the box, indicated by the second arrow. Click on "Save" when ready.
Display frequency settings can be applied to ribbons, slide ins and lightboxes.