Advance directives (ads) provide people with the opportunity to express their wishes about treatment preferences prior to becoming incapacitated. While the normative logic behind ads remain straightforward, as instruments of law they are not always effective because of questions about their validity and applicability. It is on this basis that this article attempts to resolve the legal intricacies on ads refusing treatment prior to becoming incapacitated. The author advances a thesis in support of a modification of an approach known as supported decision-making to facilitate people in making ads. This approach pre-empts most of the doubts about an ad’s validity. The argument is founded on the presumption that an ad made using the supported decision-making approach provides a higher degree of assurance about the circumstances surrounding the making of ads, rendering it more likely to be binding on healthcare professionals.