Ok I didn't realise that it had been a year already since we bought the medium size Tug Tennis Ball. I think that the dogs have got 'our' moneys worth out of it lol. So yes it was time to buy the next size of this fabulous toy & they're still loving it! Note that the tennis ball still survived.
I bought the Medium/Large size for our 13 month old Koolie & he loves playing with it. It is a great toy for him to chew, or for us to play tug-o-war with him. As the rope is a stretchy plait, it makes the play more gentle, especially when he is sharing it with our 2 month old Koolie. While he has chewed on the Tennis Ball, he hasn't destroyed it (yet), it is lasting longer than I anticipated. I highly recommend this pet toy.