Amazon just recently announced two new policies:
1. Incomplete multi part upload expiration policy : Take large files and split them up in parallels. Multi part upload feature improves the PUT performance by breaking the large files in to small parts. This increases the upload speed. But what if the upload is not complete ? You still left with some amount of S3 storage consumed and are being charged earlier. Earlier you had to remove the incomplete parts manually.
With this new policy you can set an expiration date for the incomplete upload and remove them from the storage to avoid being charged.
2. Expired object delete markers expiration policy: The S3 bucket versioning feature helps you recover from unintended user deletes or application logic failures. When you delete a versioned object, a delete marker becomes the current version of the object and the original is retained as the previous version. While you are not charged for storing delete markers, removing expired markers can improve performance for list requests on your bucket. With this launch, you can now set a lifecycle policy to automatically remove the current version delete marker when previous versions of the object no longer exist. ( As explained in AWS Blog)