Why do people wear clothes? "To make me warm and to cover my body" will (probable) be the answer. That's why people wear clothes, but people also want to look attractive and appear (success) to others.
If people only wore clothes for warmth and to cover their bodies, most clothes would be simple and cheap. In many countries, , clothes are sometimes very expensive. The main reason for that (be) not the cost of the materials or the cost of (make) clothes. The clothes are expensive because they are fashionable.
Successful businessmen, for example, often wear very expensive suits, shirts and ties. Sometimes they pay thousands of dollars a suit and several hundred dollars for tie. It's still just a suit and a tie, but they pay these prices because of the famous designer.
Fashion is changing. It means that people want to be fashionable have to buy new clothes every few months, even if last (month) clothes have been worn only once or (two). Some people have wardrobes (衣柜) full of clothes, but some of these clothes have never been worn. These clothes are no longer in fashion though they are still new.