The Remaining Useful Life (RUL) is a subjective estimate of the number of remaining years that an item, component, or system is estimated to be able to function in accordance with its intended purpose before warranting replacement. The remaining useful life is estimated based upon observations, or average estimates of similar items, components, or systems, or a combination thereof. For example, the remaining useful life of a roof with a PVC membrane that was installed approximately seven years ago and was poorly maintained might be approximately ten years. The Remaining Useful Life of building components and systems is noted in a Property Condition Assessment and is used to help calculate expected short- and long-term capital expenses required to maintain a property.