Archives expire at the same time.  Backups expire according to the
rules you select which could leave you some files expired and others
not from the same day's backup.

I've worked at two companies who use ADSM and have always used
archives for database backups.

It's much easier to recover from an archive as it will write to the same
tapes and fill them up instead of spreading out the backup over partially
filled tapes in the backup storage pools.

Sherry Jackson
The Toro Company