This is really a very cool shot....never seen players doing this before. Cutting strings! WOW! I only change mine when the "feeling" seems gone or after a certain set period. They all also seem to use these synthetic grips that are white...wonder is it also by Yonex and are they any good. White sure become dirty after very short while. Tower seems better to me but others like such rubber grips....I don't like when they start to wear....it breaks down and stain ur hands.