I heard an international student was shocked at a cosmetics store. Instead of asking, "What's your skin type?", the staff member pressed a small device against her cheek. If you search, all you get is "Korean stores measure moisture and oil with a device." ## Why measure first? Even Koreans don't know their own skin very well. Their faces look shiny, so they say, "I have oily skin," but underneath, the skin is often tight and dry. This kind of skin is called "subuji" (dehydrated oily skin). The outside and inside don't match, so measuring is faster than asking. In winter, indoor air gets dry because of heating, so your skin changes with the seasons too. Someone who had oily skin last year could have dry skin this year. ## What the device can't tell you The number on the device is the value at "that moment." It depends on whether you just washed your face or just came in from the cold outside. So it's less an accurate diagnosis and more a tool for starting a conversation. The staff member looks at that number and recommends products from the store. It also helps to know that the goal is to make a sale, so you can feel at ease. ## How to Use It Right Away - Before the measurement, tell them your condition first, like "I just came in from outside" or "I just took off my makeup." - Don't buy right away; ask, "Do you have a sample?" Just ask. Many people try it for a few days before buying. - Check the exchange and refund policy at the store or in the app before you pay. Use the numbers only as a reference, and make the final decision based on how it feels on your own skin.