A person becomes incompetent merely because the person is old or has a disease.

The notes state that aged persons and persons suffering from disease are competent unless the condition prevents them from understanding questions or answering rationally. The same functional test therefore applies rather than an automatic exclusion based on age or illness. **Key takeaway:** Age and disease trigger assessment; they do not automatically disqualify. **Glossary:** Competency test: inquiry into understanding and rational response.