Our dog is allowed on the sofa, but she loses her place first if we have guests. Actually her favourite spot is on top of the smaller sofa, looking out of the window.
She is small, non-moulting and we have leather sofas that are easily wipeable.
Years ago when we just had one cat (we now have 2 cats, a dog and two dcs), she had her own spot on the sofa and nobody was allowed to sit on her side 