If you want users to be notified when their password is about to expire, you can set up a new cronjob that searches for users based on their "Password Last Update Time" and "Password Lifetime". This cronjob is "sendexpirynotifications.php" which can be found in \extension\ezmbpaex\cronjobs. It can be run manually with the following command from the root of your eZ Publish folder:

$ php runcronjobs.php send_expiry_notifications

When the remaining lifetime of a password is less than the configured expiration notification time, an email will be generated and sent to the user so they can change their password prior to it expiring. The Expiration Notification time is defined in your mbpaex.ini and is by default set to 172800 seconds (2 days).

Per password expiry only one notification is sent to a user.