[05] WHEN AND HOW ARE ACCOUNTS EXPIRED?

    user (both prevalidated and validated) accounts are the only login
    accounts subject to automated purges.  These purges occur monthly and
    are based on your last UNIX login time if you are validated, or the
    number of days since your account was created if you are prevalidated.

    Prevalidated accounts are automatically purged whether they are in
    use or not approximately 600 days of their creation.  Validated accounts
    will expire if the user does not login at least once during a 2 year
    period.

    ARPA members are exempt from inactivity purges, though an ARPA member
    may lose their membership by violating the AUP.  When disk space becomes
    an issue, ARPA members who have not logged in for 1 year or longer may
    have their files compressed.  No files will be deleted and the user is
    welcome to login an uncompress files as needed.

    Keep in mind that using SDF for only webmail or pop3/imap service does
    not log you in to the UNIX system. You will have to login to the shell
    account regularly to avoid being flagged as an inactive account.