Heating/air conditioning units last for years, but they don't last forever. Generally, if your AC unit is over 15 years old, you should consider replacing it. You can also multiply the age of your unit by the repair cost estimate. If the result is over $5,000, you might consider replacing the unit. If your air conditioning doesn't need to be replaced, we'll tell you. We've called Staten Island, NY home for decades and would rather give you solid information than sell you a new HVAC unit you don't really need.