Acting morally comes at a price. The fewer people act morally, the dearer moral acts will be to those who perform them. Even if it could be proven that a certain moral norm were valid, the question might still be open whether, under certain circumstances, the demand to follow it meant asking too much. The validity of a moral norm is independent from actual compliance. In that regard, moral norms differ from legal rules. A law that nobody obeys has eroded and thus lost validity; a moral norm that nobody keeps, however, may still be valid. Yet the latter point does not render the question obsolete whether demanding obedience to a specific moral norm, under certain circumstances, could mean asking too much. The costs incurred might be, on the one hand, individual costs. But there may, on the other hand, also be moral costs of obeying a certain moral norm. For an individual might also have responsibilities towards others near her, e.g., her family or peers; acting in accordance with the strict moral standard, then, could do harm not just to her but also to those who rely, and must rely upon her. Yet to define moral limits to following moral rules appears to be self-defeating.