This article is a research on the economic and financial role of depreciation. Depreciation is seen as the recognition of a decrease in the value of an asset resulting from use, time, change in technique or anything else. The depreciation of an asset represents the difference between its gross value and its net book value. The difficulties in measuring this depreciation lead to the spread over a probable lifetime of the value of goods normally depreciable according to a depreciation plan. If the current value is significantly lower than the value calculated according to the depreciation plan, the loss is recorded either by way of exceptional depreciation, the remainder of the depreciation plan being modified accordingly, or by a provision when this depreciation is not considered final. Thus, depending on the priorities of the company, the costs can be treated as depreciable fixed assets, or as expenses. The company can charge the purchases of materials and tools, software, office equipment and furniture whose unit price does not exceed a certain threshold. There are two options available to the company, namely: pass its investments in fixed assets or treat them as an expense. These two situations are made possible thanks to the economic and financial role of depreciation.