Salvage value is the carrying amount of an asset after all depreciation has been fully expensed.
The residual value of an asset is based on what the company expects to receive in exchange for the sale or division of the asset at the end of its useful life.
Companies can fully depreciate their assets down to $0 because the liquidation value is minimal.
The salvage value will affect the total depreciable amount that the company uses in its depreciation schedule.