Restoring Stubs from Backup

Hi,

I Have Networker Legato For Backup of My Primary Storage and my Archive Repository.

I keep my backups for 5 years.

Every 6 Months i run my archive policy and than backup my Primary & Archive Storage

Ho long do i need to keep my orphans files before initiating orphan delete job ?

Is the Networker Backup aware of the files behind the stubs ?

How do i know what files to recover from my Archive Repository in order to keep my stubs working ?

Thanks,

Tal.