With the Recurring Billing there is an option to receive a daily email with the status of all Recurring Invoices processed that day.  If there are no Recurring Invoices, then the email will still be delivered, but it will indicate that there were no invoices processed.

To enable/disable the email:

• From the Command Center, click on Settings
• Under the Email/Text Communications Section, click on Email-SMS General Settings
• Under the Recurring Billing Settings, the control is called "Send Daily Recurring Billing Summary Report?"
• If Yes, you will need to provide a valid email address

As a default for 10.0, the setting and email is the same as "Send a Notification to Company when Invoice is Sent to Customer" setting.  So if this setting is activated, then the Recurring Invoice Email will be activated as well.