Credit rollover allows you to carry over up to two months’ worth of unused credits into the following month.
On the self-serve plans, your credits will reset each month. If, by the end of the month, you have unused credits, you can carry over up to two months' worth of unspent credits into your next. Please note that credit rollover does not apply to accounts on the free tier.
On the enterprise plans, you can decide if you want to receive your credits to reset each month or if you want them in a lump sum and then have them reset annually. If, by the end of the month or year, you have unused credits, you can carry over up to two months' worth of unspent credits into your next cycle.
This means that the absolute maximum number of credits you can have at any one time is your subscription's base allotment multiplied by 3.
As an example, if you are on the Scale plan, the maximum amount of credits you can have at any one time is 2,000,000 x 3 = 6,000,000 credits.
If you upgrade to an annual plan while you have an active monthly subscription, this will start a new annual billing cycle. Any unused credits from your previous character quota will be added to the first month's quota of your new annual plan.
If you downgrade or cancel your subscription plan, this does not take effect until the end of your current billing cycle, and unused credits are not rolled over.