HVAC units are critical home systems where comfort and reliability often outweigh purely "cheap repair" logic. With a conservative 20-year expected lifespan, it's generally sensible to repair common, lower-cost components on a Lennox-style system if the unit is not old and the quote stays under the threshold.
Examples include capacitors, contactors, blower motors, and thermostat/control issues. Major repairs-particularly compressor replacements or extensive evaporator coil work-can approach a meaningful fraction of system replacement cost, and on older equipment may not restore long-term reliability.
Consider the full context: frequent breakdowns, high energy bills, and older refrigerant types are strong signals to replace rather than keep investing. The replacement price used here is a typical installed-system benchmark from a well-known home-services cost guide; actual bids vary widely by climate, tonnage, and access.