I've used them on canoe trips under wading shoes for a week at a time. I'm constantly in the water on portages. Putting on a pair of wet, cold neoprene socks in the morning is no treat. But, if you can dry them out the night before, they aren't a problem. Regardless, wet or dry, your feet warm them up quickly and they are comfortable all day. The down side is that after a day or so, they really REEK unless you turn them inside out,rinse them out and dry them on a regular basis. Another thing, they are thicker then fabric. Make sure your boots fit with them on.