do i need to load the model again and again?

Is there any way to load a model once? 

I am experiencing with error:

Message: Undefined property: CI_Loader::$Users_model

when call for a view in my controllers.

loading the model solve it.

but do I need to load the model before any call to a view?

another error which is disappear 

Message: Call to a member function get_user_info() on null

I don't think its right way to load mode again and again.