Since product 'death' is inevitable – that is, because its design will be superseded by a new fashion or technology, or because its materials will wear out – and since industry is geared to the need for product replacement, products are engineered to die by material or mechanical failure. This makes a science out of replacement production when it is known that the product will not last more than ten years (automobiles) or not more than several weeks (batteries). Such planned obsolescence is a characteristic of every variety of consumer product and in some cases has resulted in serious accidents due to inadequate quality. The costs to the economy of planned obsolescence are incalculable.