All HeyGen plans are subscription-based, either monthly or yearly. Each plan comes with a specific amount of credits that reset when the billing cycle renews. It's important to note that any unused credits from the previous cycle will not carry over to the next cycle. This information is communicated on the pricing page before making a payment:

So any unused credits will NOT carry over.

However, HeyGen understands the need for flexibility, and we allow you to switch your plan at any time to better suit your usage requirements. When you switch plans, the change takes effect immediately, similar to purchasing a new plan. Your previously purchased credits will not be affected and will expire according to their original billing cycle.

We hope this clarifies any confusion. If you have any further questions or concerns, please feel free to let us know.