Hello @Stephen Weber
Thank you for reaching out to the Microsoft Q&A platform.
Right! Recovery services vaults are used for both backups and replication using Azure site recovery. If there is nothing in backup items blade and replication items blade, it means nothing has been protected or configured for protection under that vault. It is safe to delete.
Also, I would like to mention that the recovery services vaults doesn't cost anything. Even if there are any other configurations made like Hyper-V/VMware infrastructure, replication or backup policy, etc.,
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