I just carry a 4 fiber spokes, never had to use one though. I like the fiber or kevlar spokes because you can repair the rear wheel without having to remove the cassette which would then require carrying a chain whip, cassette tool, and a wrench, why bother? A lot of tourers carry a half a dozen real spokes that match the ones their wheels use though and they carry the tools to do it. Some tape them onto a rear stay, some inside the seat tube, some inside the handlebars if they have straight bars. But with the kevlar spokes their packaged coiled just lay flat on the bottom of a pannier.