Well, one should not smoke because smoking is injurious to health in many different ways. It increases the risk of variety of cancers like cancers of lung, bladder, oral cavity, esophagus, stomach, anus, pancreas, kidney, larynx, pharynx etc. In addition to causing lung cancer, it can cause other lung diseases like bronchitis. It also increases the risk of heart diseases. In women, smoking also increases the risk of cancer of cervix and also increases the risk of miscarriages. Therefore one should stop smoking. Its never too late!