Scratch cooking usually takes longer than cooking with convenience foods since multiple ingredients must be measured, mixed and fully cooked. Often a recipe is required, located and consulted as the food is prepared.
However, this rule-of-thumb can be misleading. Cooking time is not necessarily shorter for convenience foods. For example, it takes just as long to cook macaroni as part of a mix as it does to cook plain macaroni. While the macaroni cooks for a scratch dish, other parts of the dish can be prepared.
The cook’s skill level makes a big difference in the time required to prepare a dish. If someone cooks a certain dish often enough to have the recipe memorized and knows shortcuts, they can save much time.