Fuel's session class regenerates it's session ID automatically, with the interval defined in the session config by the key "rotation_time". By default, this happens every 300 seconds.
If you absolutely want, you can do it manually using the rotate() method of the session driver:
\Session::instance()->rotate(); // assuming the default session instance is used
thank you for the reply. I had always by practice manually regenerated after successful login, role changes, etc... Once again fuel is making things simple! I fear it's going to make me lazy
If your cookie is called "fuelcid", you're using cookies to store session data.
In that case the contents of the cookie is not the session id, but the complete session payload, which is encrypted. So quite logical it changes on every request, if only because the timestamps in the payload will have been updated.