This document discusses depreciation accounting and summarizes various depreciation methods and the objectives of depreciation. It outlines straight-line, units of production, written down value, and sum of years digits methods. It also mentions annuity, sinking fund, machine hour and depletion methods. The objectives of depreciation are stated as ascertaining true results of operations, presenting a true and fair financial position, accumulating funds for replacement, and ascertaining true production costs. Factors used to estimate depreciation amounts are historical cost, estimated useful life, and estimated residual value.