Amazon Simple Notification Service (Amazon SNS) has introduced additional usage metrics in Amazon CloudWatch for the following service quotas: ‘Topics per Account’, ‘Filter Policies per Account’, and ‘Pending Subscriptions per Account’. Under the ‘AWS/Usage’ namespace, you can now view the ‘ApproximateNumberOfTopics’, ‘ApproximateNumberOfFilterPolicies’, and ‘ApproximateNumberOfPendingSubscriptions’ metrics to monitor your usage of these Amazon SNS resources. Moreover, using AWS Service Quotas, you can also view your utilization metrics per quota, and create Amazon CloudWatch alarms to notify you when your utilization of a given quota exceeds your configurable threshold. This enables you to more precisely adapt your utilization of Amazon SNS, based on your applied quotas.
Source:: Amazon AWS