An auto mechanic is a mechanic who services and repairs automobiles, sometimes specializing in one or more automobile brands or sometimes working with any brand. In fixing cars, their main role is to diagnose and repair the problem accurately and quickly. They often have to quote prices for their customers before commencing work or after partial disassembly for inspection. Their job may involve the repair of a specific part or the replacement of one or more parts as assemblies. Basic vehicle maintenance is a fundamental part of a mechanic's work in modern industrialized countries, while in others they are only consulted when a vehicle is already showing signs of malfunction.