The age of your AC unit is a strong factor here. If your unit is 10 to 15 years old, a newer model is generally your best bet, but the cost of repairs is also a factor even in newer units. Contractors use a simple calculation to arrive at the best strategy. We multiply the age of your technology by the cost of the repair. If that number exceeds $5,000, we generally recommend replacement. Major parts like condensers and evaporators play a key role in deciding your old AC’s fate. If they’re failing regularly or require replacement, it makes better sense to invest in an entirely new air conditioner.