What is summed up in the sum of years' digits method?

The sum of years' digits method is a form of accelerated depreciation that takes into account the declining usefulness of an asset over its useful life. This methodology is not focused on a constant depreciation expense each year nor on actual usage of the asset. Instead, it determines the depreciation based on the asset's depreciable base, multiplied by a fraction that represents the remaining life of the asset in relation to its total lifespan.

Essentially, the sum of years' digits method incorporates a calculated rate that changes over time. As an asset ages, the fraction used to calculate depreciation becomes smaller, leading to higher depreciation expenses in the initial years and gradually decreasing amounts in subsequent years. This reflects the rapid initial loss of value that many assets experience.

Thus, the emphasis on the depreciable base multiplied by a calculated rate is crucial to understanding how this depreciation method allocates expenses over time, making this choice accurate in representing the sum of years' digits method.