I agree, I wish thermoflex had laces. But theoretically if they're fitted correctly their shouldn't be any extra slop, since they "mold" exactly to the shape of your foot and boot. They do pack out, but in recent years thermoflex has changed to a more of a closed cell foam material that taked longer to pack out then they used to. Also, if they do pack out they can be re-fitted whith out buying new ones to restore them to their former shape. They should be fitted wearing a thin liner sock or even no sock at all. That way when they do start to pack out a bit you can increase your foot volume by wearing a thicker sock over your liner sock.