An important concept stressed in practically every cooking class is that cooking is 10% art and 90% chemistry. Recipes are to cooks what formulas are to chemists - important instructions for a consistent result. In the same way that a chemist is only one missing ingredient away from disaster, the difference between a birthday cake and a pancake can be a pinch of baking powder. For consistent results, it is very important for cooks to follow recipes whenever possible.
One vital cooking element provided by recipes is proportion. A cook may already know the basic ingredients of a pancake batter – flour, eggs, milk and so on – but only recipes supply the proper ratio between the ingredients. There's a reason why some recipes call for two eggs, not one or three. Professional cooks who prepare these recipes already know how much flour can be incorporated into a measured amount of milk, for example. Without knowing the proper balance of ingredients provided by recipes, cooks can easily end up with glutinous masses of bread dough instead of waffle batter.
Another benefit of following recipes is consistency. An amateur cook may experiment in the kitchen and create a unique casserole or sauce, but it could prove nearly impossible to duplicate. Recipes provide all the technical and artistic elements necessary to produce and reproduce a successful product without fail. Cooks may feel inspired to change some of the proportions or flavorings, but the basic recipes will always produce the desired results. Important technical notes in recipes include cooking times, temperature settings, signs of doneness and serving instructions.
Perhaps the most compelling reason for cooks to follow recipes is the science of cooking. As stated earlier, cooking is primarily a practical exercise in chemistry. Each ingredient in recipes serves one or more specific purposes, from generating gases to creating glutens to binding other ingredients together. Eliminating one of these essential ingredients also removes the chemistry behind it. While it may be tempting to leave out a pinch of salt, for example, the remaining ingredients may not bond well without it. Many recipes call for ingredients such as baking powder or baking soda for their specific chemical properties.
There are a few instances in which traditional recipes may not be strictly necessary, but until a cook gains enough kitchen experience and learns enough cooking theory to improvise, recipes should be treated as the roadmaps to culinary success.