Physical deterioration is the reduction in value of the improvements due to the wearing out of a structure because of use, age, weather, neglect, vandalism, lack of maintenance, etc. All buildings deteriorate physically over time regardless of quality, design, or maintenance efforts. Physical deterioration is often referred to as wear and tear.
Because deterioration of individual building components may occur at different rates, building components are often analyzed separately. For example: The roof may last 20 years, the water heater may only last eight years, and the foundation may last 60 years.