and the longer we live, the more impairment will hit us. absolutely. demographers talk about what they call rectangularisation of life curves, and that is that you live to a certain age, 80 or 100 years, and then boom, you are dead at the end. and that would be perfect but that is not what we have. we go along and we decline and we decline and then we die and it is the decline which is so expensive and so problematic. which brings me to one area of impairment that i'm not sure you have spent so much time thinking and talking about or at least i have missed it, that is, not the physical but the mental and intellectual impairment. often of course that can come with old age or dementia, alzheimer's, and it affects so many people as they get older. some of the things you are talking about