According to news outlets like NPR, the New York Times and Philadelphia Metro, someone between the ages of 69 and 71 is considered elderly. Technically, a person is considered elderly if he is past middle age.
However, some people feel that the term elderly is used to describe someone who is feeble and unable to care for himself. "Elder" is also a word that denotes respect, as young people are often told to respect their elders. In the early 20th century, people generally preferred being called elderly as opposed to old. These days, it is generally agreed that older individuals who are vibrant or active may not want to be called elderly.