Choosing a ring, a stone, and a setting.
The "two months' salary" rule was written by an advertising agency. De Beers introduced it in the 1930s, when the suggestion was one month. It became two months in the 1980s. In Japan the same campaign ran with three. The number moved because it was a marketing lever, not because anything about diamonds or marriage changed. That is worth knowing before you let it anchor one of the larger purchases of your life.
