Kelly and John pretty well summed it up.
I will add that I also prefer to buy my wire cable from a quality fishing supply shop. You can get some really good plastic coated steel trace which is a lot stronger than other wire brand you are going to pick up from your local hobby shop. I also use mono leader in the 60-80 pound breaking strain from fishing supply shops for my wheel steering. My opinion mono leader material will have some slight stretch which I think benafits for using as a wheel steering and you will not notice the stretch. I will however add not to use mono leader for flight surfaces as you do not want any stretch when operating these surfaces.