Theoretically, unless the efficacy of a single product conflicts with other products, such as using photosensitive essential oil, such as Clarins Orchid Oil, and then using skin care day cream containing photosensitive ingredients. The so-called matching use of cosmetics is only a means of commercial promotion, which is used by many big brands and emphasized, but it is unnecessary in practical sense. For example, many products of Estee Lauder are not launched in complete sets, and Hao, the top brand of L 'Oré al Group, does not require complete sets, while Lancome, the second-line brand, is launched in series because of its strong commercial content.