Will Clark, 105, recently bought a van for a 5,000-mile road trip across the Midwest with his wife, Lois, who is 102.The older you get, the healthier you’ve been. People who demonstrate exceptional longevity tend to have had a lifelong history of good health. Turns out that genetic factors may account for only 20 to 30 percent of a person’s lifespan, while environmental and behavioral factors can dictate the other 70 to 80 percent.