The demandingness of morality is the cost to the agent of complying with moral demands. According to some authors, there is a limit to how much morality can demand from us, and any moral theory or principle that exceeds this limit can for that reason be rejected.
Barry, Christian & Holly Lawford-Smith (2019) On satisfying duties to assist, in Hilary Greaves & Theron Pummer (eds.) Effective Altruism: Philosophical Issues, Oxford: Oxford University Press, pp. 150–165.