I would never leave home without an extra DME Relay. Trust me, this will be the best money you ever spent if you need one. I always keep an extra in the glove box. If you do not already know how to change it (super easy with one nut under the driver seat) take a minute to learn. I would also throw in a handful of assorted fuses.
Hopefully will will have absolutely no need for the above, but for less than $100 it will be your best friend if you do need it!
Craig