A guardian is a person who is lawfully invested with the power, and charged with the duty of taking care of the person and/or managing his or her property because that person cannot do so at all or cannot do so with reasonably adequate ability (known in law as competence). The basic categories of guardianship are either of the person, of the property or both the person and the property. There are three categories of guardianship in New York which essentially differ in terms of the degree of incapacity or inability to function: (1) Guardian of children and of persons with mental retardation; (2) Conservator of a person who is substantially impaired; and, (3) Committee of a person who is incompetent.