You can set up, at the customer level, automatic task reminders.
Requirements: You must have a customer role at the customer level that includes the Modify Customer user right.
For Approvers and Reviewers, up to three reminders are provided, each with a different subject, message and sending date relative to the due date of the task.
The date options for sending task reminders are:
Tip: If you do not want the automatic task reminder to be sent from a specific task, you can define it when you create a task. In the Task Options area, select the Exclude task from automatic reminders check box.
Note: Action Task is excluded from this feature. The automatic task reminders is not sent to the task user of Action Tasks.