I'm definitely no expert, but I'm washing and drying all my fabrics first, to be on the safe side. I'm going to starch and press anyway...I'm a beginner and it takes me so long to make anything that I hope to eliminate any unpleasant surprises from shrinking. I've found that even with the prewashing and drying my flannel rag quilts "ragged" great and my prewashed cottons still look good and crinkly after washing the finished quilt!