But, like, cats wear out by use, not time. (For the most part.)
A car is good for, say, 300,000 km. If you drive 300K in it, then you "fully used" the car.
That's like saying a pad of paper isn't used when it's sitting on your shelf. Technically true, maybe, but the pad is used up when it's out of sheets. It doesn't make sense to measure the utilization time for a consumable, like paper or a car.
100% agree on "car" and came to the comments with it in mind.
As much as it sits unused the majority of the time though, that isn't what I was thinking - what I was thinking is how I've never get to "fully use" it, or any sports car I've owned for that matter, as to me fully using it would entail bringing it to a track, REALLY putting it through it's paces, and pushing it to the limits it was actually designed for. While it is great fun to drive (safely) around town, and comfort and luxury were absolutely large parts of the engineering that went into it, it's hardly living up to it's full potential!