Assets are deducted in a different manner throughout their lifespan. The main methods of are:
• Direct line amortization (constant annual amortization)
• Surplus amortization (direct line amortization calculated for the surplus value of the asset each year)
• Amount of remaining years (the ratio between the number of remaining years of the asset and the number of years that the asset is due to be used)
• Production units (equity cost of the equipment, after amortization of the accumulative amortization and of the remaining value, multiplied by the ratio between the total annual production and between the remaining recoverable reserves at the outset of any particular tax year.