Not an easy question to answer, but here are some factors to consider: 1. The age of the current system. Today, any system that is more than ten years old is probably behind the times in terms of efficiency. 2. Does the current system provide the level of comfort that you want? There is a growing difference between “builder grade” and consumer choice in what a system can offer in terms of comfort and convenience. 3. How much will the repairs cost…and how many more repairs will you need in the future? Is keeping an older system operational worth the time, the money and the inconvenience? Sometimes you need to know when to cut bait and say goodbye to your old heater or air conditioner.