Another thing that usually happens is the points themselves wear down on the cam contact side, since that side rests on the cam as it rotates. Thousands of RPM for hours on end wear it down after a while. On Bosch and Iskra and maybe a couple more they have the little piece of felt in there that touches the cam. That piece should be oiled so that it keeps oil on the cam face to help prevent wear. It doesn't take too long to remove 0.38mm.