Start a little snug or you will be sliding around in them later. The lambswool will smash down some and the boot stretches. A friend wears hers without socks. She swears they breath enough to not get sweaty, but she only wears them a few hours. I live in mine. LOVE how they feel, but alas they have become a little unfresh. So, try them on with socks if you will wear them all day. Try them on bare footed if only for short times. And, start snug.