It would depend on the degree of Ed being experienced, your age, your other medical conditions (diabetes, hypertension, etc. In some patients, 1/2 a tablet, or even 1/4 a tablet Might be sufficient. As the person ages, develops diabetes, high blood pressure, etc., the dosage might need to be increased. Eventually, if you live long enough, Ed may become very difficult to treat with Cialis, Levitra, etc., and you may need to go to a drug called Muse (alprostadil). And if you continue to age and further lose erectile function, eventually you can reach a point where nothing helps anymore. At that point, you are said to have intractible erectile dysfunction, and nothing can help you. Hopefully that will be years off for you. And by then, you won't care.
half a wood...