A person with dementia should not be left alone when there is a clear and present risk to their safety or wellbeing. Specific situations that indicate 24-hour supervision is needed include a history of falls, a tendency to wander and become lost, an inability to recognise or respond to household dangers, significant confusion about time and place, an inability to call for help if something goes wrong, or advanced physical frailty. Emotional vulnerability is also a factor, as some people with dementia experience severe anxiety when alone. A social services care needs assessment can formally evaluate what level of supervision is appropriate.