As I understand this, a cast iron frying pan works best when seasoned. If it's seasoned, there's a layer of oil or grease over the cast iron so that food doesn't stick to it so much. When a cast iron frying pan is washed, it usually needs to be re-seasoned. That means coating the cooking surface with oil or grease and heating it up in the oven. It's usually less work to just wipe the pan out before next use than to wash it thoroughly and re-season it. That's also why you usually use more oil or grease when cooking with cast iron compare to cooking with porcelain or teflon, so that less food gets stuck to the surface.
A teflon frying pan, however, needs to be kept clean and needs to be handled carefully. If the teflon coating begins flaking off, the pan needs to be thrown in the garbage. Teflon is fine for cooking on as long as it stays bonded to the pan and doesn't get into the food. It's an extremely persistent material that you cannot digest.
