Beyond 15 years old, HVAC equipment faces exponentially higher failure rates

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

Whether a new HVAC system is worth it depends primarily on your equipment's age and documented failure-curve data