Am I loading a class twice?

[eluser]Buso[/eluser]
It wont be any performance hit, but the method (is_logged_in) could have referenced $this (the user instance) or an instance attribute and it wouldn't have worked, so the usual way is calling get_instance()->user->is_logged_in(), or using an extra helper is_logged_in(), which calls the above.

Even if it works now, the implementation of User::is_logged_in() could change, and after an update your code wouldn't be compatible with it anymore