The design life of a component or product is the period of time during which the item is expected by its designers to work within its specified parameters; in other words, the life expectancy of the item. Engineers follow a

theory A theory is a systematic and rational form of abstract thinking about a phenomenon, or the conclusions derived from such thinking. It involves contemplative and logical reasoning, often supported by processes such as observation, experimentation, ...

to calculate the life expectancy from expected conditions, uses and physical properties. It is not always the actual length of time between placement into service of a single item and that item's onset of wearout. Another use of the term design life deals with

consumer products A final good or consumer good is a final product ready for sale that is used by the consumer to satisfy current wants or needs, unlike an intermediate good, which is used to produce other goods. A microwave oven or a bicycle is a final good. Whe ...

. Many products employ design life as one factor of their differentiation from competing products and components. A

disposable camera A disposable or single-use camera is a simple box camera meant to be used once. Most use fixed-focus lenses. Some are equipped with an integrated flash unit, and there are even waterproof versions for underwater photography. Internally, the c ...

is designed to withstand a short life, whilst an expensive

single-lens reflex camera In photography, a single-lens reflex camera (SLR) is a type of camera that uses a mirror and prism system to allow photographers to view through the lens and see exactly what will be captured. SLRs became the dominant design for professional a ...

may be expected to have a design life measured in years or decades.

Long design lives

Some products designed for heavy or demanding use are so well-made that they are retained and used well beyond their design life. Some

public transport Public transport (also known as public transit, mass transit, or simply transit) are forms of transport available to the general public. It typically uses a fixed schedule, route and charges a fixed fare. There is no rigid definition of whic ...

vehicles A vehicle () is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to land vehicles such as human-powered vehicles (e.g. bicycles, tricycles, velomobiles), animal-powered tr ...

come into this category, as do a number of artificial satellites and

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

. In general, entry-level products—those at the lowest end of the price range fulfilling a certain specification—will tend to have shorter design lives than more expensive products fulfilling the same function, since there are savings to be made in using designs that are cheaper to implement, or, conversely, costs to be passed onto the customer in engineering to provide a safe margin leading to an increased working life. This

economic An economy is an area of the Production (economics), production, Distribution (economics), distribution and trade, as well as Consumption (economics), consumption of Goods (economics), goods and Service (economics), services. In general, it is ...

truism leads to the phenomenon of products designed (or appearing to be designed) to last only so long as their warranty period.

Obsolescence

Design life is related to but distinct from the concept of

planned obsolescence In economics and industrial design, planned obsolescence (also called built-in obsolescence or premature obsolescence) is the concept of policies planning or designing a good (economics), product with an artificially limited Product lifetime, u ...

. The latter is the somewhat more nebulous notion that products are designed so as to become

obsolete Obsolescence is the process of becoming antiquated, out of date, old-fashioned, no longer in general use, or no longer useful, or the condition of being in such a state. When used in a biological sense, it means imperfect or rudimentary when comp ...

—at least in the eyes of the user—before the end of their design life. Two classic examples here are

digital camera A digital camera, also called a digicam, is a camera that captures photographs in Digital data storage, digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film or film stock. Dig ...

s, which become genuinely obsolete as a result of the very rapid rate of technological advances, although still in perfect working order; and non-digital

cameras A camera is an instrument used to capture and store images and videos, either digitally via an electronic image sensor, or chemically via a light-sensitive material such as photographic film. As a pivotal technology in the fields of photograp ...

, which are perceived as obsolete after a year or so as they are no longer "the latest design" although actually capable of years of useful service.

References

* *''Design for the Real World: Human Ecology and Social Change'', Victor Papanek, Academy Chicago Publishers; 2nd Rev edition (December 1985), {{DEFAULTSORT:Design Life Industrial design Product design Sustainable design

Long design lives

Obsolescence

See also

References