An open access review paper looks at how the study of fly aging has informed the life sciences: "it is likely that not all senescent physiological changes revealed in flies can be simply translated to humans. However, flies and humans often show very similar age-related physiological phenotypes suggesting that at least some of the basic biological properties and mechanisms that regulate longevity are conserved amongst species. ... It is well-known that advances in medicine and health care have significantly contributed to increased longevity in humans over the last 100 years. There is also a clear trend toward increased life expectancy including an increase in the numbers of people living to an advanced age and the number of people with chronic age-related diseases. These trends emphasize the need to understand the genetic and physiological factors underlying biological aging and particularly, those that promote healthy aging. ... there are three ways to extend lifespan: increasing early survival rate, increasing late survival rate, or delaying senescence. Remarkably, the first two do not affect basic aging processes. For example, the first one leads to a significant increase in mean but not maximum lifespan, while the second one leads to change in a maximum but not mean lifespan. Delayed senescence, in turn, leads to a significant increase in both the mean and maximum lifespan. ... This raises the question as to whether healthspan and delayed senescence are inter related. As stated above, while many genes have been shown to extend lifespan, these may have little or no ability to delay physiological senescence. In other words, the period of functional disability before death may increase despite the fact that the total duration of life is increased. Thus, the search for appropriate biomarkers applicable to monitor functional senescence is highly important with regards to healthy aging and age-related diseases." These cautions are very much focused on the mainstream research goals of slowing the rate of aging through genetic and metabolic alterations; they have little relevance to efforts aimed at producing continuous repair of aging.