Against Malmo until min 60, we didn't score and yet we were playing with 5 defenders. Juve barely changes formation, especially during the game.
We never changed formation while Conte was here. Games vs RM were an exception, as we'd be in for a rough ride with only Licht and Asa on the flanks, while Bale, Ronaldo and Di Maria would have a field day. I only pointed out that with current players and coach who is flexible enough to try something different it is possible for us to make a switch at one point if things don't go our way. I don't expect any trouble tonight with our current setup, as Milan side is rather mediocre and extremely vulnerable at the back. Parma scored 4 goals last week against them, and that tells you all you need to know about their composure and organization at the back.
Btw we rarely play with 5 defenders, as Licht and Asamoah stay high up the pitch. Sometimes, on rare occasions you can them dropping deep, which occurs when opponent has possession for longer periods; but that is indeed rare.