Emcee0, please have a look at page 61 of the manual under the topic:
Policy recommendations for Exchange Server 2007 ...
Create a policy that backs up the
Information Store, a storage group, or an individual database. This policy supports full, incremental, and user-directed backups.
To perform the backup with Granular Recovery Technology (GRT)
select the Enable granular recovery option.
Then you can restore databases and
individual mailbox and public folder items. You cannot restore these individual items from any incremental backups that use GRT.
The above, IMHO, answers your question...
If you do not want to configure GRT due to the requirements, you can still backup the Information Store, and if you really want to be able to restore individual items, configure a separate policy to backup Mailboxes and/or Public Folders (p.103). Care should be taken to not run these policies at the same time. Most customers prefer to only backup IS and use Recovery Storage Group to restore certain components.
Extract from page 105:
MAPI mailbox and public folder backups allow for mailbox or public folder recovery, but are not adequate for disaster recovery. Exchange database
backups are required for disaster recovery.