In considering whether or not to install HID bulb upgrade modifications, I'm wondering 2 questions; 1) Are the bulbs much less dependable than regular incandescants? Do you need to change them more often, or less? And 2), how available are the bulbs. Just more stuff to store on a long ride? If your'e out on a 3 week ride and one goes out in the middle of nowhere, are they almost impossible to replace?