Recently I traded strings with John Hempel, and he sent me years-old strings. Mines were all bought in this summer. If you were the person to buy different kinds of strings and trade them, you would not get years-old string on your racquet to ruin your games or even arm and shoulder. He refuses to take the strings back. Please be careful when you trade with him. You might get a bunch of garbage or strings at the cost of your arm and shoulder.