In the world of interfaces and interaction design, cognitive models (sometimes metaphors) change rapidly as new ideas arise. This rapid change often creates fatigue and even cognitive dissonance in users who have to relearn the use of a device, a Web site, an application, or even a system. Some strategies for reducing this problem and lengthening the lifespan of these devices and services include the following:
• Design interfaces and systems with future needs in mind wherever possible. Consider total customer needs and design models that take these into account, even if not all features will be available in the beginning. 
• Choose metaphors that won’t get old quickly (or don’t use one at all).
Design interfaces and systems with future needs in mind wherever possible.
bility, both inside and outside the company. (For example, some automobile companies give magazine reviewers their car models to drive for several years in order to review them over the car’s lifetime.)
Where possible, when broken components of a more complex product can be exchanged for a new replacement, the result is a more sustainable solution that minimizes material and energy impact. Imagine having to junk a car when the battery died or throw away a printer when the ink ran out? As silly as these examples sound, there are plenty of products that aren’t designed for replacement of components, requiring perfectly fine undamaged components to be recycled or disposed of unnecessarily. Apple’s iPods and iPhone are examples of this and mar otherwise admirable and advanced sustainable designs. Most televisions and smaller kitchen appliances (everything but dishwashers, stoves, and refrigerators) suffer the same fate. When one component fails, such as the pump on a coffee maker, it’s usually impossible to get a replacement part, or the labor and cost involved in installing it far exceeds the value of the appliance itself.