Leaders and Enders are fabrics pieces used to start and end a chain of sewing. Often a leader is just a small scrap of fabric that is run through the machine over and over as needed. Using a leader/ender will conserve the use of thread, prevent “bird nests”, save time and can reduce wear and tear on a sewing machine.
Many quilters keep a pile of prepared patchwork pieces (such as HSTs) beside their machine and run these through rather than use a scrap. In this way, they actually sew new units together which they will keep to use in a later project rather than wasting thread on a scrap that will eventually be thrown away..