I’d be interested to know what makes you think the dealer who delivered your brand-new car has changed the tyres. Were they showing signs of wear? Did they make the car handle or ride strangely? Did they just not look 'right’?

I can’t imagine any dealership would be stupid enough to fit partly worn tyres on a brand-new car. You bought a new car, it should come with new tyres. Simple as that, and anything else is pretty shifty to say the least. The dealer might have switched to another set of brand-new tyres if one or more of the originals was damaged, but that’s not what you’ve suggested here. I’d definitely be taking it up with Nissan Australia’s customer service division as selling a brand-new car with second-hand tyres just seems crazy. Not to mention legally questionable.

If it’s simply the case that the tyres’ tread didn’t look brand-new, then the 26km it’s already covered could explain that by taking the shine off the tread. That, and the fact that the sidewalls were probably still very shiny (dealerships love tyre-shine products) could make the treads look worn when they really weren’t.

The faulty tyre-pressure monitoring system is a separate issue and can be fixed by replacing the dud parts. This is a simple warranty claim, and even though tyres are generally not covered in a new-car warranty, selling a brand-new car without brand-new tyres is a new one for me. If it really did happen, you’d be well within your rights to demand brand-new tyres.

If this was an older car, the explanation would be simple: Cars always have at least a driver on board, but sometimes only a driver. Which means that the driver’s seat gets worn out faster than any other seat in the car. But you car is quite new, so that shouldn’t be the case.

Assuming there’s no manufacturing flaw in the seat or the way it’s mounted, the cause of this could be as simple as a driver’s seat that has more adjustments available (manual or electrically-operated) than the front passenger’s seat. If that’s the case, you might find that the mechanics of those adjustments gobble up some space that is used for foam or other padding in the not-so-adjustable passenger’s chair.

The high cost of complex replacement parts for relatively new vehicles is a trend that has been thriving lately. Once some cars are more than a handful of years old, a replacement engine or transmission can easily exceed the value of the whole car. At which point, owners have a tough decision to make; replace the car or pay up for the fix.

Aside from the financial aspects, you also have to decide how comfortable you are unloading a ticking time bomb on to a potentially unsuspecting buyer