During a carriage tour of Mackinac Island with my son last week the tour guide (a college student with an entertaining, if not poorly paid, summer job) took us by the three cemeteries on the island, the Catholic Cemetery, the Protestant Cemetery and the Post Cemetery. While passing one of the cemeteries (I believe the Protestant Cemetery) the guide noted that therein lies the longest surviving person buried on the island, a woman who lived to what I recall was maybe eighty-four-years old. He then commented on the unusualness of her longevity given that the average lifespan at the time of her death (mid-1800s) was about forty-one. Unfortunately, her longevity was not that unusual.
The following example illustrates the guide's mistake in understanding of average life expectancy at birth and living to a ripe old age.
Orchestra conductors live to an average age of eighty-nine years, while the random person has an average life expectancy at birth of 78. We can therefore conclude that being an orchestra conductor is better for your health, which translates into an increase in your expected lifespan.
Notice, however, the wording in my sentence above. "Orchestra conductors live to an average age of eighty-nine-years," and "the random person has an average life expectancy at birth of 78." The former is an average age of death of orchestra conductors taken at the time they died, while the latter is an average age of death for all people, including infants who died shortly after birth, young children who died before the age of five, older children who died before ten, teenagers who died from accidents, etc.
In order to become an orchestra conductor one has to survive beyond the age of, say, thirty. Once he reaches his thirtieth birthday he can't die at 1 or 2 or 10 or 20 years of age. As you get older you can expect to live to an older age relative to years past only because something didn't already kill you at a younger age.
Yes, this woman buried in the Protestant Cemetery was fortunate to not have succumbed to some disease or accident at a young age, but it certainly wasn't unusual. Go to a cemetery and you'll see many tombstones for people buried in the 1800s who lived well into their seventies and eighties. You'll also see tombstones for kids buried during that time who didn't make it past their fifth birthday. In fact, far more than what you'll see for kids born since, say, 1950. For that I am grateful for our market capitalist institutions.