Long johns, also known as thermal underwear, are good for anyone who needs to stay warm in cold weather. They can be particularly beneficial for people who work or spend a lot of time outdoors, such as construction workers, skiers, snowboarders, hunters, and hikers. Long johns are also popular among people who live in colder climates and need an extra layer of warmth to stay comfortable in daily activities. Additionally, long johns can be beneficial for people who are more sensitive to cold, such as older adults or people with medical conditions that affect circulation. Overall, long johns can be a practical and useful addition to anyone's cold weather wardrobe.