Incremental Forever - Expiration

Im Confused as Well by this…

The Introduction States …

WD Arkeia can be configured with “Forever Incremental Backups” instead of performing Full Backups on a weekly or monthly basis.
However, the Incremental Backup Level must have an expiration date to ensure storage capacity stability.

 

This would seem to imply the backups that are set to expire in XX time would be deleted in order to “ensure storage capacity stability”.  Acording to your comments though this appears to be not true.

Do you have a suggestion as to how to setup a disk backup that only backups new files from a path since the last backup and that expire and are automatically deleted from the backup server at an interval of lets say 2 weeks.?  I do not need a FULL backup of the path as there are a lot of files in the path I dont need.  I apologise if my understanding of the backup system is inept.

Thanks