Amazon S3 offers different storage classes for storing objects. One of the storage classes is Intelligent Tiering. It transitions objects between different tiers based on how frequently they are accessed, in a fully managed automatic way, and can lead to significant cost savings.
Intelligent Tiering sets up a monitoring mechanism that tracks when your object was last accessed. Objects that are not accessed are transitioned to cheaper storage tiers. Objects that are accessed are automatically moved back to the frequent access tier. This is done without any degradation to performance or added operational procedures.