I do not permit people to register on my webiste, as I have a limited group of people that I want to have membership. Anyway, I create a user account for the person, and email them a username and password.

Now, depsite my best efforts, some users are not changing their passwords. I would like to force the user to change their password - either on first login, when the admin sets a flag against the account, or after a set number of days since last login.

Is this possible? Has anyone implemented any or all of the ideas?