Yes. If you are on a monthly plan, your paid credits expire in 60 days, so they will roll over for one month. If you are on a yearly plan, all your credits will be valid for 13 months! You'll receive a full year's worth of credits immediately after your purchase. All credits will expire after 13 months.

If you cancel subscription, the remaining credits will expire at their own expiration time, even if it’s after the end of the billing circle.