Our knees are arguably one of our most important joints, but also one of the most poorly looked after. Science tells us putting in some work now pays dividends later. You might start to notice it as early as your thirties: the dull knee aches when the weather changes, the morning stiffness when you get out of bed. You might think twice about crouching down. They're all unwelcome signs that your knees are not quite the well-oiled joints they once were. (BBC News)