Plenty of companies lean on rules of thumb to justify equipment sales that aren't necessary. Here's the honest version: if your system is under 10 years old and the repair is a single component failure, fix it. If it's 14 years old, needs refrigerant, and this is the second major repair in two years, the math on replacement starts to work. We'll tell you which situation you're actually in — and we don't have a financial reason to steer you either way. If you want a second opinion on a quote you've already received, we offer free HVAC second opinions with no obligation.