I don't mind washing full 1/4 or 1/2 yard cuts - it's the fat quarters and other precuts that I don't wash. I normally do wash all my fabrics. In fact am working with a bazillion 1/4 yard cuts of batiks now which were all washed. However, coming from a kit - I honestly don't know what I would do. There is such a risk of running out of fabrics. When washing the fabrics after getting them on grain they are frequently quite skewed and you lose quite a bit when straightening the edge. You could always just cut one layer and start your straight edge on the short end of the piece as an alternative.