This is for security purposes.
Many companies require users to change their passwords frequently, in some cases once a month.
At Salem State, we don't require you to do that, but the hardware is set up to do it a few times a year. You may want to change your password more frequently, especially if you are in a highly trafficked area, or share your computer with a group of people. It is not an indication that you are paranoid or think your office mates are untrustworthy, it is just common sense in a world where so much is controlled through and kept on computers.