1. Depletion:
Assets such as mines, quarries, etc. are of wasting nature. By extraction of these natural depositions, their value is reduced. This reduction in value of natural deposition due to depletion in quantity is a cause of depreciation.
2. Scrap value:
This is the estimated value of a fixed asset at the end of its useful life. It is the amount which is expected to be received when the asset is sold after being removed from service. It is also known as Salvage value or residual or Break-up value of asset.
3. Obsolescence:
As a result of change in fashion or new inventions, some assets may be discarded before their productive life comes to an end. This is called obsolescence.