For me i have only one facebook id and it is good to have only one,so that i can remember my everythings,so why you are asking these question,is there any reason for this?
I have an account but i dont use it so much it bugs me so many things on it and people are always wanting something from you, plus many things to allow for no reason and even if you allow them they dont work they are viruses or somebody`s page to make money.
In my opinion facebook is not for everybody.