I am wondering what happens to the old model when there is a minor change to the current model. Looking at Pure Drive, the price difference is only $30. Is it typical discount amount? It doesn't sound much to me. But Pure Drive is the most popular model, so that may be why the discount is very small. And how long are the old one usually available? Could the used rackets be even cheaper? I was thinking about buying Yonex Vcore 100S, but I just heard that new one is on the way (late November). Thanks.