Bill Burr Password Guru had once advised users to change their password every 90 days and to modifier words by adding capital letters, numbers and symbols – so, for example, “protected” might become “pr0t3cT3d4!”. he believed his theory will help to protect the user from a computer hacker, who use a different technique to access user private file. However, Mr Burr now acknowledges that his 2003 manual was “barking up the wrong tree”.
...................https://www.nibbleng.com/password-guru-regrets/