Depreciation is the systematic reduction in the value of a tangible asset over its useful life due to wear and tear, passage of time, usage, and normal deterioration. In construction management, depreciation is an important concept because construction equipment, machinery, buildings, and other fixed assets lose their service potential gradually while being used in projects. Depreciation helps in determining the true cost of using an asset, assists in estimating project costs accurately, and enables proper financial planning. It is also necessary for accounting purposes, taxation, replacement planning, and evaluating the economic life of construction assets. Methods such as straight-line method, diminishing balance method, sinking fund method, and machine hour method are commonly used to calculate depreciation depending on the nature and usage pattern of the asset. Obsolescence, depletion, and amortisation are concepts related to depreciation but differ in terms of the type of asset involved and the cause