<P> Considering the time value of money is central to most engineering economic analyses . Cash flows are discounted using an interest rate, except in the most basic economic studies . </P> <P> For each problem, there are usually many possible alternatives . One option that must be considered in each analysis, and is often the choice, is the do nothing alternative . The opportunity cost of making one choice over another must also be considered . There are also non-economic factors to be considered, like color, style, public image, etc.; such factors are termed attributes . </P> <P> Costs as well as revenues are considered, for each alternative, for an analysis period that is either a fixed number of years or the estimated life of the project . The salvage value is often forgotten, but is important, and is either the net cost or revenue for decommissioning the project . </P> <P> Some other topics that may be addressed in engineering economics are inflation, uncertainty, replacements, depreciation, resource depletion, taxes, tax credits, accounting, cost estimations, or capital financing . All these topics are primary skills and knowledge areas in the field of cost engineering . </P>

Describe the importance of economics for technicians /engineers