You may think it’s the former, but with the state of the fashion industry, it’s likely the latter. She told Vox that what’s known as fast fashion has been kicked into hyperdrive by companies like Shein. “The way it works is that they use algorithms to track trends and what people are interested in, and then they make a few hundred of a very large number of different items and they test demand. ” She says this model has allowed companies like Shein to introduce around 4,700 new apparel styles per day. ) Some are trying to claw back their personal style by hitting the thrift store instead.