Renewal notices will always be sent out for members who are subscribed to non-recurring billing plans. The notices on these plans should relay the information that their subscription has almost run out and it is time to renew.
Members who are subscribed to a recurring billing plan will only receive a renewal notice when the member's credit card will be expired during the next billing cycle. The renewal message will only be sent out if a message has been entered in the 'Renew Message' form field for that member plan. If no message has been entered in the form field, the member will not be notified their credit card is expired.
The message that is entered into the 'Renew Message' field might include information about when the subscription will be renewed, their credit card is expired and where to update their card information.
It is a good idea that the wording of the plans and even the Welcome Message is clear enough so members know they will be automatically paying every month or year (depending on the plan).