A number of years ago, I pulled into work very early in the morning and just before exiting the car I could smell smoke and saw that there must have been a short in the under dash wiring. I was very thankful to have my fire extinguisher right beside me in the car. I had a little mess to clean up, a tow to the shop and relatively small cost to trace all the problems and get them fixed.
Be sure to maintain them in good working order.