Welcome, from Louisiana. I do prewash EVERYTHING.. I learned the hard way. I had used a beautiful, deep blue, unwashed cotton to make piping for a smocked dress. When the dress was finished, I spritzed it with water before the final pressing and the blue color ran all over the white dress...What a mess! It was a customer dress and I had to buy more fabric and smock a whole new dress! So, NOW I prewash!
Karen in la.