When your rule is active, Facebook checks if your campaign, ad set or ad meets the rule's conditions and then notifies you of the rule's results. Depending on your rule, rule checks occur continuously (at least every 30 minutes) or daily (at 12:00 AM in your ad account's time zone) until your campaign, ad set or ad ends. When you create a rule, you can see how frequent the rule will run:

You can also check the Activity table to see how frequent your rule runs.

* Nguồn: Facebook