Passwords expire "to the minute" 90 days after your password was last changed. If you're in the middle of a referral or document and that "minute" comes up, you will lose any data not saved (you have to get out of SAFE - NOT saving changes and call the Helpdesk to have a new password created). PLEASE make sure you change your password BEFORE the day it tells you it expires.
SAFE Password Requirements
Click for more information on SAFE Password requirements