A gunsmith is a person who repairs, modifies, designs, or builds guns. The occupation differs from an armorer, who usually replaces only worn parts in standard firearms. Gunsmiths do modifications and changes to a firearm that may require a very high level of craftsmanship, requiring the skills of a top-level machinist, a very skilled woodworker, and even an engineer. Gunsmiths perform factory-level repairs and renovations to restore well-used or deteriorated firearms to new condition. They may make alterations to adapt sporting guns to better fit the individual shooter that may require extensive modifications to the firearm's stocks and metal parts. Repairs and redesigns may require fabrication and fitting of unavailable parts and assemblies constructed by smiths themselves. Gunsmiths may also renew metal finishes or apply decorative carvings or engravings to guns. Many gun shops offer gunsmithing service on the premises.