Length of time jobs are kept on backup files

Q:

How long are jobs kept on backup GDG files before deleted?

A:

For as long as the backup GDG file is cataloged to the z/OS system. In other words, they are never actually deleted from the backups. They remain there as restorable jobs until the backup GDG file is deleted or uncataloged from the z/OS and/or disk or tape management systems.