When you originally set up your Hosted Exchange mailbox password or change your mailbox password, that starts a 1000-day window until the next required password change.
1000 days = roughly 2 years 9 months.
The mailbox user will be sent an email notice about 2 weeks before the 1000 days and the email will come from this email address [email protected]. The notification email will just state that their password is going to expire soon and to log in and reset the password or have your assigned Hosted Exchange Admin reset it for you.
However be prepared to update all your devices, like your Email Client (Manager), phones & tablets. For phones and tablets, it might be easier just to delete your mailbox and reinstall it with the new password.
updated January 2, 2024
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