I worked for few Clean-Up processes to delete after few days. So its leads to one idea have an entity level life time like 30-days 60-days 90-days unlimited by default its will be unlimited on persistable entity. If we select for 30 days then the objects of that entity will get deleted after 30 days of creation.
The main goal of this feature is there is no need to run manual flows to find past some days records and delete.
In case of associations we will maintain in association level if Object A delete Delete Object B too.