Depends if, I see the name of a player or not during the match. If theres a first half without see the name of a ST or MC/AM* I do a sub aprox in the min 50', but, all depend of, if I have the control of the match, because sometimes is good idea change the best player that have 8* fior another and sometimes is better, for avQ. keep this and first, before do subs, I try to move players between lines to see if the arrive better to the goal.

Then usually I do one when match is arround to the 80' or more.