depends. you want to keep the player or you are planning to sell him? do you have chances to win trophies this season or you are out of your competitions? if you want to sell the player his quality must end on 4 or 9. you will get good money and even tokens (if he 's good and 39 quality and above). i apply them to SA or second position in order not to change star. this way only this season i have earned about 20 tokens by selling 5 not needed players. if you dont have chances to win a trophy you should save them for next season. he is going to train faster and your lower quality is good for next season 's competitions.