Mailbox sizes have been increased in Exchange 2010. By default users will receive a 1 GB mailbox
There are three quota levels. Exceeding each quota level has different results. The results for each level are as follows:
Level 1: User will receive daily notification emails stating the the user must reduce mailbox size. Notifications will continue until mailbox size is under Level 1 quota.
Level 2: User will not be able to send mail until mailbox size is under Level 2 quota.
Level 3: User will not be able to send nor receive mail until mailbox size is under Level 3 quota.
Quotas for Staff:
Level 1: 900 MB
Level 2: 1000 MB
Level 3: 1100 MB
How do I check my email quota?