Password Expiration Best Practices
It's best to set the password for Lisa in your property management (PM), email, and calendar systems to never expire. If the password expires, Lisa will stop working until the engineers can update the password.
In general, expiring passwords are considered security flaws:
By default, passwords are set to never expire. Current research strongly indicates that mandated password changes do more harm than good. They drive users to choose weaker passwords, re-use passwords, or update old passwords in ways that are easily guessed by hackers.
from Microsoft Outlook help site
These pages describe how to adjust password expiration: