You can now choose an Amazon Elastic File System (Amazon EFS) Lifecycle Management policy to automatically move files that haven’t been accessed for 7 days into the EFS Infrequent Access (EFS IA) storage class and save up to 92% as your access patterns change. You can configure this new policy option for your file system, or you can use one of the existing policy options: 14, 30, 60, or 90 days. 

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/11/amazon-elastic-file-system-infrequent-access-now-supports-7-day-lifecycle-management-policy/