Product Review - Setting Review Request delay
Setting Review Request delay
The number of days that pass between a customer making a purchase and being asked for a review with a follow up request email can be determined by the Administrator of the website. This is useful for many reasons, such as allowing the customer some time to try out the product, when products are generally being purchased close to holiday seasons and so on.
To do this Navigate to System → Configuration → Catalog → Product Review Coupon, then open up the section labeled Email Sending if it isn't already open.
In the field labeled "Delay sending email to clients by the number of hours" enter the number of hours that must pass before the email is sent to the customer.
Click on "Save Config" in the top right of the screen.