Sofa furniture is undoubtedly a sofa. The sofa beds are made mostly of wood, the upholstery is mostly fabric, leathercloth or leather. You can buy or order a sofa bed in any color, size or style. It is up to you whether the sofa bed will serve for everyday or just occasional sleeping. For a sofa bed, you need a little more space, because it occupies more space in the exploded state.
Not every time you need to swap a sofa bed for a double, it depends how many people will sleep on it, in the folded state serves quite well as a single. However, the sofa is not only for sleeping, but is intended for a pleasant lounging, for example, after a good meal. The sofa, whether fixed or folded, is the center of each living room, so you should pay attention to it to tune with other furniture in the living area.