Only once. What I do is pause the game, turn on debug mode, select skip day, turn back off debug and take the game off pause. This was working before and still works with one lot but the others are borked. I've tried uninstalling the timer from the family and buying a new one, even moving them out bulldozing the lot and moving them to another but it still doesn't work properly. I was trying to see if it was anything special or different I was doing like turning aging on/off, playing the family through a day, then trying to skip but no combination seems to trigger it to work again.