If you’ve ever wondered why some perfumes that smell almost identical are named—and priced—differently, you be interested to know that these naming conventions indicate different levels of fragrance concentration. The most concentrated is Perfume, second most, Eau de Perfume, third, Eau de Toilette, and least concentrated is Eau de Cologne. The more concentrated it is, the longer you can expect the scent to last and the less you should use. There is no magic amount to use, but as a rule of thumb, two spritzes directly to skin should always be plenty—sometimes too much. Before wearing a new perfume out, test out its potency at home. Try one spritz on a pulse point, dabbing excess on others, and make note of how strong it is. Then, check in every couple of hours and access how it's holding up.