How many items on your vintage car or bike cost less than $10, but could leave you stranded someplace? It turns out that there are quite a few, and I thought it would be interesting to list those that I have personally experienced. It would be great to get your additions in the comments, but here they are :
Points: These critical ignition system components are simple, inexpensive, and wear over time. Not a problem back in the day when every auto parts store stocked them, but try getting a set for your 2002 at the Autozone in western Arkansas. This is enough of a problem that several companies are in the business of providing better performing electronic ignition systems (eg: Pertronix, Crane) that do not wear. However, try finding a Pertronix Ignitor at the Autozone in western Arkansas. Many vintage owners (myself included) carry points in a Ziploc in the toolkit to revert to if the electronics fail. What irony, eh?
Condensor: The partner in crime of the points. Unlike points, they often fail without notice. Same remedy as points, and I have one in the Ziploc.
Bleed Nipple: These can seize in the caliper or snap off on removal (always a fun time). However, if you need one in a metric size, they may not be around.
Wiper Blade: I had one of these liberate itself from the wiper stalk. In pouring rain. At night. Thankfully, it did not score the windshield, but try finding a comparable one at the Autozone in western Arkansas. In the rain. At night. I ended up taking the stalk off the passenger side and using the wiper blade.
Spark Plug : I once needed a plug for my 356 which had failed. It turned out to be unavailable at the 2 nearest auto parts places. I got lucky at the third place which was a NAPA.
Brake Light Bulb: Ok, technically this does not disable the vehicle, but it can be downright dangerous to run around without brake lights. Bulbs of the type you need may have been commonly available once, but there is no guarantee today.
Ignition Key: I had one almost break in half far from home. Fortunately, a friend at the rally had a key blank, and I got one made. A near miss that has me carry a blank on the keyring of that vehicle ever since.
Carburetor Floats: Age and pinholes cause this inexpensive part to fail flooding your carbs and making your bike run like a wounded rhino.