When choosing sports socks, first consider your shoes. Lightweight competition shoes, such as track spikes or cycling shoes, may fit more comfortably with a thinner sock than the thicker style you wear for long practice sessions in heavier training shoes. But if you like the extra padding that thicker socks provide, stick with them on competition day. Make sure you test the shoe/sock combination in practice first, and be consistent with what you wear during your training period and competition day. When you find a fit you like, buy similar socks when you buy new shoes.