Office 365 passwords expires by default every 90 days. If this setting is too short, you can modify the number of days from the Office 365 Administration screen which can be accessed by following these steps:
- On the header/top menu, click on Admin
- On the Left navigation menu, click on service settings
- On the content top menu, click on passwords
- Enter the number of days next to the Days before password expire text box.
This is an image of how this should look on the new Office 365 with SharePoint 2013.
|Office 365 - Password Expiration Days|
We can also note that the notification settings can be updated from this view. By default, it is set to 14 days. This means that 14 days prior to a password expiring, the user gets a notification indicating that the password is about to expire.