Pro account credits may roll over depending on the type of credit and the status of the Pro account.
Subscription Credits
Subscription credits are included with your Pro subscription. They refill monthly as long as your Pro subscription is active. Subscription credits do not roll over.
Top-up Credits
Top-up credits are additional credits you can purchase when you've run out of Subscription credits. All Top-up credits will roll over with an active Pro subscription.
Important Note: If you cancel your Pro subscription, you can learn more about what happens to your credits here: What happens to my credits if I cancel?