Some sites, such as CNET, store the login details in a cookie. If I clean those cookies I have to reenter them.
For other sites, see https://support.mozilla.org/en-US/kb/password-manager-remember-delete-change-passwords
Kees
I am using Windows 7 and have recently switched to Mozilla Firefox. There are certain sites that I am happy for my user name to be retained to speed up access to those sites. How can I save the username details for such sites [this was not an issue with IE]?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic