Subsequent costs should meet the same recognition
criteria for capitalisation as the initial expenditure on
the asset, i.e., when it is probable that future economic
benefits associated with the item will flow to the entity
and the cost of the item can be measured reliably.
If part of an asset is replaced, the old part is
derecognised (even if not previously depreciated
separately), and the new part is capitalised provided the
recognition criteria are met.