What is a valance and do I need one?

A valance is not a bed essential. Valance refers to an extra length of fabric extending beyond the regular edges of a bed cover (see bed covers, specifically bedspreads and comfortspreads) which looks much like a curtain and is designed to hang prettily to the floor down the sides of the bed and is purely for decoration. It is a great and simple way to dress up a bed which may be seen by any visitors or guests. It provides a more fitted look than a standard bedspread, which is an over-sized blanket also designed to reach down to the floor.