Americans are living longer, with average life expectancy in the U.S. rising from age 71 in 1970 to age 79 last year, leading many to stay employed far past retirement age. Paul Solman reports on some of the oldest workers of all, and the lessons they can share, as part of our series, “Unfinished Business." PBS News is supported by - https://www.pbs.org/newshour/about/funders