How long does a dishwasher typically last? When should the roof be replaced? How long do air conditioners operate efficiently? For home owners, or those considering buying a home, these and many similar questions are common. While there are no hard and fast rules, there are general guidelines that can help set expectations for the life expectancy of home appliances, systems and components. Varied conditions and levels of care can affect longevity, and many components will benefit from regular maintenance.