I don't think it is relevant "who" changes "what" (you or a specialized technician). The point revolves more around whether replacing a vital component after o

I don't think it is relevant "who" changes "what" (you or a specialized technician). The point revolves more around whether replacing a vital component after only one year of normal use would be covered by warranty (in EU for consumers warranty is two years for everything). Another interesting point is how you discover that some part needs to be replaced. For the car, it is easy, one morning it won't start. What if (say) Ford or Chevrolet (or Volkswagen that has some documented experience in the field ;)) had a hidden electronic device that - in order to save the battery and your next morning start of the car - progressively dimmed a litte bit your head and tail lights and/or lowered the heating or the cooling set temperature slightly, starting, still say, after six month?