quick question - today my trainer pulled out a ball bucket with about 150 balls that seemed like a century old. dirty grey, no bounce, sounded like flat tyres. i mean these were dead-as-dodo balls! we had to hit the life out of the ball to get it across, and there was only a tiny bounce, he said it was gr8 for rallies. i recalled reading an interview in which Bartoli said she often practices with dead balls. is this a good idea? any thoughts?