Would an average lifespan of 120 years be a blessing or a burden?

This question assumes, hypothetically, that people could live to an average age of 120 and asks what longer lives would mean for individuals and society. It does not claim that such an era has already arrived. The implications for care, retirement, housing and resources shared between generations depend on whether the years of healthy, active life also increase. The discussion distinguishes length of life from quality of life and considers the possibility that access to longer lives could be concentrated among only some people.