Prevent Office 365 Password Expiration

In Office 365, when not using ADFS or DirSync with Password Sync, you can disable password expiration through PowerShell.
Once you establish a PowerShell session to your Office 365 tenant, run:

Set-MsolUser "username" -PasswordNeverExpires $True

To change it for all users, you can use:

Get-MSOLUser | Set-MsolUser -PasswordNeverExpires $True