Heavens, No! You can make all kinds of yummy things with extra sourdough starter! (Start with my mom's sourdough hotcakes or our delicious Cranberry Crumb Sourdough Coffee Cake recipe.) If, however, you have more starter on hand than you anticipate using for baking, you will need to toss (or share!) a cup or more, and then double what remains. You always want to have at least 8 ounces of Starter after baking to keep the process going.  After you feed it, allow the starter rest in a dark, warm place (70°F) for 12 hours, and then place in the refrigerator if you will not be using it in the next 24 hours.