When creating user accounts and Mailboxes in Office 365 the default Microsoft password policy is applied, which means you have to change your password every 90 days.
While it is a best practice to change your password on a regular basis not every customer is too happy with this. I can think of one exception and that’s a service account, this makes sense to have the password set to never expire.
To change this option for user accounts in Office 365 you have to use the Windows Azure Active Directory PowerShell module to connect to Office 365 using the following commands:
$msolcred = get-credential connect-msolservice -credential $msolcred