Audiophiles are often told that their new equipment, components or cables need to be 'broken in' to deliver their best performance. So far, technical backup of the phenomenon is (with the exception of mechanical changes in speaker drivers with use), non-existent. However, Doug Self found that there may be something to it. He found that the distortion in polyester capacitors drops significantly with use, and that the improvement is to a large extend, permanent. This extends the earlier work of Cyril Bateman.