Which method does not change the depreciation rate throughout the asset's useful life?

The straight-line method is a depreciation approach that allocates an equal amount of an asset's cost to each period of its useful life. This method is straightforward because it uses a consistent expense amount each year, calculated by taking the cost of the asset, subtracting any salvage value, and dividing that by the asset's estimated useful life in years.

This consistency in the amount expensed means that the depreciation rate remains unchanged throughout the asset's life. Thus, businesses can predict their annual depreciation expenses easily, which aids in budgeting and financial planning.

In contrast, methods such as the unit production method vary based on usage, meaning the depreciation expense can change each period depending on how much the asset was used. Similarly, the double declining balance method and the sum of years' digits method result in higher depreciation amounts in the earlier years of an asset's life that gradually decline, altering the rate and total expense recognized over the asset's life.