Old age comprises "the later part of life; the period of life after youth and middle age . Most developed-world countries have accepted the chronological age of 50 years as a definition of 'elderly' or older person.
The United Nations has agreed that 65 years may be usually denoted as old age and this is the first attempt at an international definition of old age.
The age at which these discounts are available varies between 55, 60, 62 or 65, and other criteria may also apply.
Sometimes a special "senior discount card" or other proof of age needs to be obtained and produced to show entitlement.
It has come into widespread use in recent decades in legislation, commerce, and common speech.
The marks of old age are so unlike the marks of middle age that legal scholar Richard Posner suggests that, as an individual transitions into old age, he/she can be thought of as different persons "time-sharing" the same identity. Gillick, a baby boomer, accuses her contemporaries of believing that by proper exercise and diet they can avoid the scourges of old age and proceed from middle age to death.
Other writers treat the perceptions of middle-age people regarding their own old age. Studies find that many people in the 55–75 range can postpone morbidity by practicing healthy lifestyles. Minois comments that the scribe's "cry shows that nothing has changed in the drama of decrepitude between the age of the Pharaoh and the atomic age" and "expresses all the anguish of old people in the past and the present." Lillian Rubin, active in her 80s as an author, sociologist, and psychotherapist, opens her book 60 on Up: The Truth about Aging in America with "getting old sucks. Rubin contrasts the "real old age" with the "rosy pictures" painted by middle-age writers. Morrison delineates the heroism required by old age: to live through the disintegration of one's own body or that of someone you love. been with us since the stage of primitive society; it was both the source of wisdom and of infirmity, experience and decrepitude, of prestige and suffering." "Beauty and strength" were esteemed and old age was viewed as defiling and ugly.
In commercial contexts, where it may serve as a marketing device to attract customers, the age is often significantly lower.
In Canada, the OAS (Old Age Security) pension is available at 65 (the Conservative government of Stephen Harper had planned to gradually increase the age of eligibility to 67, starting in the years 2023–2029, although the Liberal government of Justin Trudeau is considering leaving it at 65), and the CPP (Canada Pension Plan) as early as age 60.
Many people are also willing to get involved in community and activist organizations to promote their well-being. The heart is forgetful and cannot recall yesterday. The general understanding is that those who lived into their 40's were treated with respect and awe.