@VigilantFox 40 years.
However, if that same boy successfully made it to age 5, his remaining life expectancy jumped significantly, giving him a clear path to reach his 70s.
@VigilantFox infant and child mortality rate.
Historically, if a person survived the dangerous periods of infancy and childhood (under the age of 5), they had a very high probability of living into their 60s, 70s, or even 80s.
In 1841, a newborn boy in England had a life expectancy of about