Ceramic Voltage resistors

Ther's a guy called Murphy that must be factored in here. He says if you keep a spare in the glove box the one under the hood will never fail. For the $3-$5 bucks for the spare it's cheap insurance.

And, yes the ballast resistor was the most common part to fail in the ignition system. I believe the bad rap came from the real early ones that the coil of wire was exposed on the bacside to the elements. New ones are potted and do not fail any where near as often.