We currently offer monthly billing. Your billed by license blocks based on the date of purchase of those blocks. License will be renewed before your due expiration date unless you cancel your subscription before. You have the ability to lower your subscription blocks by individual licenses during any time during the month of your subscription, however there is not a pro-rated credit for early reduction of licenses during the billing cycle. This is due to the fact that we do not delete the data associated with that license and any work within the system will still be accessible.