How bad is taking tylenol (acetaminophen) or aspirin each day, if done according to label? i know it's not good, but i get headaches almost each day, maybe rebound?

Not harmful,not good: Taking Aspirin or tylenol (acetaminophen) every day is not harmful in that it will not kill you, and if you are obeying the label it is unlikely that you will do any serious damage to any organs. You are correct, however, that taking tylenol (acetaminophen) or any otc pain med (or fiorcet, percocet, vicodin, etc). Frequently can put you in a rebound cycle which will make treating your headaches very difficult.