Account 0021 Plant/Machinery Depreciation belongs to the group of assets accounts ( due to its number) whereas account 8001 Plant/Machinery Depreciation belongs to the group of expenses accounts ( due to its number ). They both have to do with depreciation. In what situations we would use 0021 rather than 8001 and in what situations we would use 8001 rather than 0021. I am a bit confused because those two accounts have the same names.