Ship breaking or ship demolition is a type of ship disposal involving the breaking up of ships for scrap recycling. Most ships have a lifespan of a few decades before there is so much wear that refitting and repair become uneconomical. Ship breaking allows materials from the ship, especially steel, to be recycled. Equipment on board the vessel can also be reused. As an alternative to ship breaking, ships are also sunk to make artificial reefs after being cleaned up.