Inactive (30 & 90) - Based on the zimbraLastLogonTimestampFrequency.
Default is 7d to cutdown on ldap writes every time you auth. You can set it to values like: 1d, 1h, 1m, 1s, or 0 for disabled.
The server will update the user's zimbraLastLogonTimestamp user attribute at most once every zimbraLastLogonTimestampFrequency.
zmprov mcf zimbraLastLogonTimestampFrequency 3d
Think of the pure volume of some systems, updating an attribute for a half-million+ active users all day long makes for a lot of writes and replication. Prompted implementation of: Bug 18972 - provide way to completely disable zimbraLastLogonTimestamp (setting to 0).
Your /opt/zimbra/log/audit.log is continuous anyways so you can always check that. There is a database entry in zimbra.mailbox for last_soap_access (getLastSoapAccessTime) not ported to a LDAP value because that would be nuts. For some, 7 days does seem a little high though given the average installation size and faster systems. To that end, someone had an bugzilla entry in to get the default changed from 7d > 3d but I don't know what happened to it. If you have the time/ability for a large scale performance test go for it.
Non-Active - Accounts not in the active state (see below).
Active - Normal status for a mailbox account. Mail is delivered and users can log into the client interface.
LockOut - Users who try to log in and do not enter their correct password are locked out of their account after a specified number of consecutive failed login attempts. An account’s status is automatically changed to Lockout. How long the account is locked out is set by COS or Account configuration, but you can change the lockout status at any time.
Maintenance - When a mailbox status is set to maintenance, login is disabled, and mail addressed to the account is queued at the MTA. An account can be set to maintenance mode for backing up, importing or restoring the mailbox.
Locked - When a mailbox status is locked, the user cannot log in, but mail is still delivered to the account. The locked status can be set, if you suspect that a mail account has been hacked or is being used in an unauthorized manner.
Closed - When a mailbox status is closed, the login is disabled, and messages are bounced. This status is used to soft-delete an account before deleting the account from the server. A closed account does not change the account license.