Customer is an ongoing photographic project that began in 2020, exploring the relationship between consumerism and personal identity through the collection of thermal paper receipts. Each receipt, often discarded as a trivial object, records fragments of daily life: what we buy, where we go, and how we participate in systems of exchange. Unlike conventional photographic materials, thermal receipts are unstable and non-permanent; the original print gradually fades over time, and each receipt exists as a unique object that cannot be truly reproduced. This challenges the traditional understanding of photography as a reproducible medium. By transforming these receipts into portrait-like images, the work redefines portraiture beyond physical appearance, using consumption patterns as reflections of character, memory, and social position. In exhibitions, the work is presented as scanned images at real scale, allowing viewers to compare the portraits directly. The more a person spends, the more receipts they accumulate, resulting in larger images and a stronger visual presence.