I usually describe the period of history and type of militaria that I collect. Some people collect guns or bayonets, only. Some collect uniforms or medals or hats. For example one area that I collect is British Regimental Cap Badges. Each person has their own reason for collecting a specific type of militaria. Some want to collect from a certain period. Others may collect only items related to Paratroopers or Aviators. Some will collect Maps because they are colorful. And some collect things that they think will increase in value. It is a personal taste.