Non-current asset are used to produce, deliver goods or services and maintaining day to day operations.
At the period end, non-current assets needs to be depreciated to account for economic benefits (revenue) generated from the use of assets.
Exception: Land is never depreciated, as it has infinite useful life. Land & building are often brought and sold together. Therefore, market value of land needs to be separated from total purchase or selling price when calculating depreciation.
IAS 16 Property, Plant & Equipment provides guidance on depreciation of non-current assets.