 Staple length is an important criterion for spinning fibre, as shorter fibres are more difficult to spin than longer ones, so staple length varies from short to longer length fibres, short fibers also resulting in more hairy yarns.For cotton and wool, staple length was originally tested by hand, the tester removing a clump of fibre and then arranging it on a dark cloth for measurement.In the 1970s, machines were invented to do this task, taking around 5 minutes for cotton and for wool around 20 minutes.