Harite and shinshi make it possible for the dyer to stretch fabric mid-air, allowing the dye to dry quickly and evenly. In general, I recommend spacing your shinshi about a foot apart, with the harite clamps at the ends. That means that a one-yard length would require one set of harite and only two shinshi. A twelve-yard length would require, thirty-five sticks plus the clamps.  If you happen to have ten on hand when you stretch a one-yard length, it's a good idea to space them closer and use them all.  If you happen to have only ten on hand when stretching your twelve-yard length, simply use what you have and make do.
   However, do consider purchasing a few extra when you place your order as back-ups. After fifty years of using these, I've consistently found that you can never have too many on hand.