Three aspects of territoriality are important to consider when planning nursing care: a physical space of one's own, a personal space, and the territory of expertise or role. Territoriality serves four functions: it provides security, privacy, autonomy, and self-identity, all of which are important for well-being. Many factors, such as age, sex, culture, and health status, affect the way people relate spatially to one another. The nurse should assess territorial needs routinely by asking the patient questions and by observing him in his environment. If the patient is in his own home, she should avoid invading his territory without his permission and should help him maintain and protect his territory. If the patient must leave his own home to be hospitalized, she should help him establish a temporary territory elsewhere and help him adapt to the loss of his own physical space, personal space, and/or territory of expertise and role. Careful attention to territorial needs, particularly when the person is ill, at a vulnerable age, or is facing a move, can contribute a great deal to his health and well-being.