Password aging is a mechanism that allows the system to enforce a
certain lifetime for passwords. While this may be moderately
inconvenient for users, it ensures that passwords are changed
occasionally, which is a good security practice. Most Linux
distributions do not enable password aging by default, but it's very
easy to enable.
By editing /etc/login.defs, you can specify a few parameters to set the default settings for password aging:
change These values as you want. change 9999 to 7 to enforce all users to change their password every 7 days.