What are GAAP-estimated useful lives on fixed assets?

Depreciation is the method of allocating costs to the appropriate period. Although accountants have to follow generally accepted accounting principles (GAAP) for financial statement reporting purposes, they have different allowable methods to consider. -Three are methods based on time: straight-line, declining-balance, and sum-of-the-years’ digits. The last, units-of-production: is based on actual physical usage of the fixed asset. Here’s a brief explanation of each: 1- القسط الثابت • Straight-line: This method spreads the cost of the fixed asset evenly over its useful life. 2- القسط المتناقص • Declining-balance: An accelerated method of depreciation, it results in higher depreciation expense in the earlier years of ownership. 3- مجموع أرقام السنوات • Sum-of-the-years’ digits: Compute depreciation expense by adding all years of the fixed asset’s expected useful life and factoring in which year you are currently in, as compared to the total number of years. 4- حجم الإنتاج • Units-of-production: The total estimated number of units the fixed asset will produce over its expected useful life, as compared to the number of units produced in the current accounting period, is used to calculate depreciation expense