In the US, the answer depends on what depreciation you are
reporting - financial or tax. They are two different
creatures. Depending on the assets, the numbers can be the
same but its not likely.
For the financial reporting your company should have a
policy on asset life depending on asset class. Computers
and like could be 3 years, autos could be 2 years,
furniture and fixtures could be 5 years. For the tax
depreciation, the US government provides the dollar
limits, asset life, the specifics,
Talk to your certified accountant.