  The period histograms of eclipsing binaries generated with ASAS data cannot
only be interpreted by orbital evolution. The eclipse probabilities, selection
effects and space distributions in the solar neighborhood should be considered
before any interpretations are made. Depending upon physical dimensions (total
mass and period) of the progenitor stars and the efficiency of angular momentum
loss (AML) mechanism, a newly formed W UMa type binary can be at any age up to
several Gyr, and evolution in the contact stage is controlled not only by
angular momentum and mass loss but also by mass transfer between the component
stars. Thus, mean life of contact stages should be about 1.6 Gyr. A different
time scale would cause inconsistencies.
