I always put an fuse in the circuit running to any accessory. They are inexpensive and good insurance to protect the electrical circuit. I tape a spare fuse to the outside of the fuse holder. I also made up a test light which plugs into the connector for the heated sheild. That way I can periodically plug it in to make sure the circuit is powered. I have had problems with the cord going from the electrical connector coming from under the handlebar pad to the sheild, the light let's me pinpoint the problem quickly while out on the trails. I carry a spare cord while on the long saddlebag trips just in case.
Jim