Upon reaching 12 to 15 years, compressor and capacitor failures account for most HVAC breakdowns

https://precisionhvacrepair-after-hours-sac-near-university-park6171.urbanvellum.com/posts/furnace-service-timing-depends-on-documented-age-and-cost-ratio-thresholds-for-repair-viability

A properly maintained HVAC system typically lasts 12–15 years, but component-level failure—especially compressor breakdown or capacitor burnout—often determines actual lifespan well before that