Mailbox & Google Drive space is 30GB combined. Archived items still count against your space. Thus, the best policy is to clean as you go. As it stands, FPI will not be increasing space for users who reach their maximum. FPI pays for a 10 year email archiving service on all mailboxes. Thus, any mail you clean out can be recovered from the archiving tool.
Please download the attachment to find out some tricks on keeping your mailbox clean.
Additional questions can be directed to firstname.lastname@example.org
Clean as you go, thank you!