I do a lot of running and have gone through a number of different socks for running. Other synthetic socks seem to cause me to slip inside my shoes a bit. They also pick up a lot of lint, hair, and other stuff when walking around the house. This stuff is really hard to get off in the wash because it gets stuck in the fabric. The under armor socks are AWESOME. Not only are they true to size, but they do not slide around at all. I wear them to work all day and then also when I run or exercise. Don't get my feet to hot either.