If you receive a failed charge email, update your payment method in your dashboard so your subscription stays active. This can happen after a trial converts to a paid plan or when a recurring payment fails — see Proxy trials: free 2-day and introductory pricing on rotating plans for trial billing context.

If PayPal cannot charge you for some reason, we receive a cancellation request on your PayPal subscription. This can make your package automatically terminated on the due date.

Of course you can wait till it terminates to resubscribe, but is it really that necessary?

You don't really have to wait for it to terminate. If you receive a failed charge email, you can simply login to your package and update the payment details as per the screenshot.

If you wanted to stop the subscription instead, see How do I cancel my subscription?.