Currently the only available way to alert customers that their subscriptions are renewing is to select the "subscription renewal ahead" email. The problem with this is that if my business sells multiple products to our customers which all renew at the same time, the customer receives an email for each item which is really annoying for our customer who receive numerous items. I have one customer who receives 7 Subscription renewal ahead emails all on the same day!!
I wish that there was a "Invoice Renewal Ahead" email that groups all of their subscriptions onto one email the same way that I select the invoice consolidation option so that the customer receives one invoice rather than 7.