We're subjected to periodic intervals of multiple attacks which can only occasionally be monitored.
Usually animals (and people) sleep at periodic intervals, such as once a day.
The light extends from each side to the middle and retracts again at periodic intervals.
If pivotal events occur at periodic intervals, culture will evolve in regular phases.
Then, at periodic intervals, and if all parties agreed, the full conference would reconvene to hear reports from the separate negotiating groups.
At periodic intervals the plates were removed, weighed, and the customer billed.
In common with most organisations we have a requirement placed on us to provide a head count at periodic intervals.
As a consequence the lights were now mounted on wooden posts set into the ground at periodic intervals.
Sometimes there is a guaranteed minimum reviewed at periodic intervals.
This system relies upon the ability of the electorate to elect and dismiss leaders at periodic intervals.