It all depends on when, what, how and how many.
For cakes: 48 hours is preffered. However, we very often book up on Fridays and Saturdays for orders, so the more notice the better. A week is usually enough.
For cupcakes: If ordering directly off the menu and no special decorations and what have you, then the day before you need them at the latest. Again, the more notice, the better the guarantee you get your order. Special orders requiring icing colors, additional decorations, etc we would need the 48 hours and keep in mind that our weekend days are very busy.