With home ovens and family size amounts, the basic answer is, not really.

If you keep something in the same size pan, for example, you make 1 cake layer instead of two, or one loaf instead of two, the time would decrease only a minute or two.

With baking, the good idea is to keep the layer about the same thickness it was in the original recipe by decreasing the size of the pan. Thinner layer DO cook faster, thicker one usually DO require a 10-25 degree drop in temperature and some extra cooking time to avoid burning edges while cooking the thicker layer all the way through.

You might consider baking the full recipe and freezing half, where the item is freezer-friendly.