Moodle has other settings related to passwords. One thing that you might want to do is to go into your Moodle, Administration, and search for the word "password" to get a sense of other "password" settings.
In my case (above), I believe that since I have set "enable password expiry" to no, this then nullifies the other two settings.
When you create a new user, there is a setting for the new user "Force password change." If you enable this, the first time the student logs in they will have to set a new password. If your password duration is 30 days, then they will have to change their password after 30 days. My guess is that if you do not force a password change when creating a user, the password duration begins from when their account was created. (I would have to test this.)
When I use self-enrollment, students get to pick their password when they sign up for Moodle. In my case, I am not enforcing password changes. This is my personal performance. However, most IT departments at schools will force password changes.
In my case (above), I believe that since I have set "enable password expiry" to no, this then nullifies the other two settings.
When you create a new user, there is a setting for the new user "Force password change." If you enable this, the first time the student logs in they will have to set a new password. If your password duration is 30 days, then they will have to change their password after 30 days. My guess is that if you do not force a password change when creating a user, the password duration begins from when their account was created. (I would have to test this.)
When I use self-enrollment, students get to pick their password when they sign up for Moodle. In my case, I am not enforcing password changes. This is my personal performance. However, most IT departments at schools will force password changes.
I am not sure what happens if you are using some kind of authentication method other than self-enrollment.