Mitsubishi Electric is widely recognized in ductless and heat-pump categories, and repair economics can differ from basic single-stage central systems because electronics and refrigerant work are often the highest-cost items. Using a conservative 17.5-year lifespan (based on typical manufacturer guidance that many AC systems last 15-20 years), it's generally reasonable to repair under the threshold for common service items such as fan motors, blower motors, and basic electrical components when the system is not old.
Replacement becomes a more conservative decision when an older unit develops compressor problems, recurring refrigerant leaks, or expensive inverter/control board failures, since those repairs can be costly and may not restore long-term reliability. Also consider comfort goals: newer variable-speed heat pumps may provide better humidity control and lower operating costs, which can justify replacement earlier than "end-of-life." The replacement price benchmark reflects a typical installed-system cost from national home-services pricing guides; actual ductless system bids vary widely by number of zones, line-set complexity, and region.