We are becoming a nation of planners living quantified lives. But life accumulates competing risks. By preventing heart disease and cancer, we live longer and so increase our risk of suffering cognitive losses so disabling that our caregivers then have to decide not just how, but how long, we will live. The bioethicist Dena Davis has argued that emerging biomarkers that may someday predict whether one is developing the earliest pathology of Alzheimer’s disease (like brain amyloid, measured with a PET scan) are an opportunity for people to schedule their suicide. Or at least start smoking.

Our culture of aging is one of extremes. You are either healthy and executing vigorous efforts to build your health account, or you are dying. And yet, as we start to “ache in the places where [we] used to play,” as one of Mr. Cohen’s songs puts it, we want to focus on the present. Many of my older patients and their caregivers complain that they spend their days going from one doctor visit to the next, and data from the National Health Interview Survey suggests one reason. Among older adults whose nine-year mortality risk is 75 percent or greater, from one-third to as many as one-half are still receiving cancer-screening tests that are no longer recommended.

I don’t plan to celebrate my 80th birthday with a cigarette or a colonoscopy, and I don’t want my aging experience reduced to an online, actuarial accounting exercise. I recently gave a talk about Alzheimer’s disease to a community group. During the question and answer session, one man exclaimed, “Why doesn’t Medicare pay us all to have dinner and two glasses of wine once a week with friends?”