Me and my friend where talking about this for a while: You are playing a match, it is match point for the other player. its your serve, you get two balls like normal but one ball is perfect, brand new. but the other ball is total crap, like 5 years old so flat that if you stand on it it compleatly compresses. the ball is so dirty its not even yellow, its brown. Do you use the bad ball on your first serve, so you can get some ok pace on it. or do you use good ball on first serve so you can just kill it, try to get any ace or somthing. but if the first serve goes out or hits the net then you are screwed.