Accelerated depreciation is an accounting method used by companies to reduce their tax burden. It involves depreciating assets more quickly than the straight-line method, resulting in higher present value of tax depreciation in early years. The accelerated depreciation method includes double-declining balance and sum of year's digit methods, which are commonly used by companies for both financial and tax purposes. However, there are limitations to this method, such as lower deduction in future years and recaptured depreciation. Companies use accelerated depreciation to minimize start-up deductions, cost minimization, and cash flow, but it may not be suitable for all businesses due to record-keeping requirements and taxable income consistency.