People who live below their means share a handful of quiet habits that set them apart, and the research suggests the difference is far less about how much they earn than about a single trait almost anyone can build

From the outside, living below your means can look like deprivation, or plain stinginess. Watch the people who actually do it, though, and that is rarely how it feels to them. They are not white-knuckling their way past every temptation; they have arranged li…