On 1 January 2015, Best Ltd purchased a new machine for $72,000 with a useful life of 5 years and a residual value of $2,000. The company performs regular maintenance and repairs $350 each year in order to keep the machine running. On 1 July 2019, Best Ltd decided to completely overhaul the machine's major operating parts at a cost of $8,000. After the major overhaul, the machine is expected to have a useful life of 3 more years and a revised residual value of $3,500. Best Ltd uses the straight-line depreciation method. On 31 December 2021, Best Ltd sold the machine for cash $12,000. Best Ltd prepares adjusting entries at the end of every financial year and the company's financial year ends on 30 June. Required 1. Prepare the general journal entry to record (4 marks) a) the machine's depreciation expense for the financial year ended 30 June 2015; b) the machine's depreciation expense for the financial year ended 30 June 2020; c) the sale of the machine on 31 December 2021. 2. Are depreciation charges really necessary? What subjective decisions or estimates are involved in accounting for depreciation? (4 marks)