Thanks for the reply Genny, but would you mind clarifying what you mean by "make sure the group is clean..."? I am not sure I understand.

So is it better to group rather then combine all the items that make up an object so you don't have to select individual faces then apply a shader?

Take the door frame in this image Would it be good practice to have the main door as one object the frame as another and setback paneling left and right of the door another, so 4 items in total?

Sorry this might seem basic but I am trying to figure out what would be best practice?