Change your password on a schedule

Passwords are like bubble gum; they are better when fresh. The longer and more complex your password is, the harder it is to crack, and the less often you'll need to change it. If you use an 8-character password, you should change it about every six months. Remember: Never use a password with less than 8 characters. If you use a 9-character password and follow the rules about uppercase and lowercase letters, numbers, and symbols, it will stay fresh for a whole year. If you can't remember the last time you changed your password, it's time to change it.

                                                       -- from the SANS Tip of the Day.