1. Straight-line depreciation is the simplest and most often used technique, in which the company estimates the salvage value of the asset at the end of the period during which it will be used to generate revenue (useful life). The company will then expense a portion of original cost in equal increments over that period. The salvage value (residual value or scrap value) is an estimate of the value of the asset at the time it will be sold or disposed of.