We have clients who take our services on Annual payment once a year of specific dates. This can be same for those in business of Vehicle insurance, personal Insurance, Annual premiums, Annual domain renewal reminders.
Where we may like to set up a Yearly recurring email going on a particular date every year to remind and then a follow up recurring email, until a date or a few number of weeks.
I am not sure how your team has missed such an important recurring email settings to provide in your paid service? It may be the last mile you need to achieve if you are interested to make your service perfect.