HI Barry,
In case if you are pointing to the user-quota alert which is sent to end user as part of the quota breach then it is sent only once through the event existence.
If your question is for an alert which is configured for the user-quota soft limit breach then there is no direct option for this.
Try this workaround:
Open up Alert wizard->Recipients->Notification Frequency: Select Remind Every "60 minutes" between "09" and "10" hours. Save the alert.
This will ensure that you receive repeated alert only once everyday between 09:00 hours and 10:00 hours.
