There are two things that define the frequency of an action: the schedule of the rule (down at the bottom) and the frequency that you set right in certain kinds of tasks. 

Consider the following example:

We set up the rule that would increase the budget of all adsets by 10% every 1 hour and set the rule checking frequency to every 15 minutes.

The bottom schedule defines when and how often a rule runs the checks. A rule may get triggered or not but it still runs the checks according to this general schedule.

As for the additional schedule setting in the tasks, it allows you to set a maximum frequency of actions for each individual ad set. Meaning that if it's every 1 hour then even if the rule runs the checks say, every 15 minutes, each ad set will not be affected more often than every hour.

If there are any questions left don't hesitate to reach out! We'd be glad to help ;)

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