Get the real safety by periodical check for the automotive wire and insulated cable
The metal sheath and solid filling of mineral-insulated cable (MI cable) makes it mechanically robust and resistant to impact; an MI cable may be struck repeatedly with a hammer and still provide adequate insulation resistance for a circuit [2]. Copper sheathing is waterproof and resistant to ultraviolet light and many corrosive elements. MI cable is approved by electrical codes for use in areas with hazardous concentrations of flammable gas in air; an MI cable will not allow propagation of an explosion inside the copper tube, and the cable is unlikely to initiate an explosion even during circuit fault conditions. Metal sheathing will not contribute fuel or hazardous combustion products to a fire, and cannot propagate a fire along a cable tray or within a building. The insulated cable is inherently fire-rated without additional coatings, and will survive designated fire tests representative of actual fire conditions longer than the enclosing structure.
People usually think that the really important parts for the vehicles are the engine, GPS, steering system and pay for maintenance of these equipment. However, the part really does effect the operation directly might be the automotive wire, the device used to be the connection and transfer signal.
Why the automotive wire could effect the operation? For example, you may have a perfect steering system with ABS, but can you image what would happen if the signal transmission is dead and the vehicle has no reaction for your control? Or, if the lighting does now work well at night, you have a ignition system in great condition, but can you drive without lighting?
Therefore, for prevent these situations to endanger the safety of driving; besides the main system, maybe you should tell the repairman to pay more attention on the status of auto wiring parts as well.