You can edit the schedule for an update.
If you want the schedule to apply to the entire index, click All content sources.
By default, if you select Daily and want to repeat the task, the content source is updated starting at 12 A.M. every 5 minutes for 24 hours (1440 minutes), and the update repeats every day.
For example, you can schedule a crawl that runs every 5 minutes every day during business hours. To do this, schedule a daily update starting at 9:00 A.M. Select the Repeat task check box, specify a Task interval of 5 minutes, specify a Task duration of 480 minutes (8 hours), and specify a Schedule interval of 1 day. The crawl runs every day every 5 minutes between 9 A.M. and 5 P.M.
By default, if you select Weekly and want to repeat the task, the content source is updated starting at 12 A.M. every 5 minutes for 24 hours (1440 minutes), and the update repeats on the day of the week on which you create the schedule.