Clothes tend to be cheaper in Taiwan than in western countries. If you happen to be bigger or taller than typical sized Taiwanese people, you may want to bring most of your clothes with you. Western brand name clothes- Levi’s, GAP, Polo, etc will be more expensive in Taiwan than back home, but imitation Polo, Levi’s and GAP clothes will be far cheaper in Taiwan. Natural fiber clothes can be more difficult to locate in Taiwan.
The rule of thumb is comfortable casual- as long as you aren’t wearing jeans and a t-shirt, and your clothes aren’t dirty or wrinkled, you will be fine. It is important to note, however, that Taiwanese are image conscious, and you will be treated with far more respect if you dress nicely – pretty much a standard statement anywhere.