I use these exclusively to sleep in. They are ridiculously soft and warm. My uggs, which I use as the perfect slippers for wearing around the house, come off at bedtime and these come on. Then the uggs come back on in the morning. I live in the Pacific Northwest, where feet have reasons to be cold pretty much year round. But this combo, with strict discipline to leave the Old Friends for sleeping only, completely solves the cold feet problem in a tidy and deeply comforting way.