1. We recommend to run Cron once per hour.
2. Cron checks up to 100 zones. If you have for example 200 zones, Cron will check zones from 1 to 100 first, then it will check zones from 101 to 200.
3. If the zone is inactive or missconfigured for longer than 24 hours, Cron will automatically delete it. Single Cron run removes up to 5 such zones.