The amount of oil you should use in a frying pan can vary depending on the size of the pan and the specific recipe you're following. However, as a general guideline, you'll typically want to use enough oil to create a thin, even layer on the bottom of the pan.
A rough estimate is to use about 1-2 tablespoons of oil for a standard-sized frying pan with a diameter of around 9-10 inches (23-25 cm). This amount of oil is usually sufficient for sautéing or shallow frying ingredients.
Keep in mind that certain dishes or cooking techniques may require more or less oil. For example, deep frying will require a larger amount of oil to fully submerge the food. Conversely, if you're trying to reduce oil consumption, you can use less oil or employ cooking techniques like pan-searing or stir-frying that require minimal oil.
It's also worth considering the type of food you're cooking. Ingredients that release a lot of moisture, such as mushrooms or tomatoes, may require a bit more oil to prevent sticking.
Remember to adjust the amount of oil based on your personal preferences and the specific recipe instructions you're following.