Many cases present the question of how sharp must the testator be? Most cases where the signing was supervised by an attorney invariably present the assertation: “she was fine”. Less lucidity is required for the execution of a will than to enter into a contract or sign similar legal documents. In practice this is thought to be illustrated by the view that more capacity is required to buy a car or a house than is required to make a valid will in New York.
New York law also provides a presumption that a person who signs her will has the requisite capacity to do so.
The cases often focus on advanced age or mental infirmities, and while these considerations are relevant they are not themselves determinative.