Beyond 12 years, the 50% cost threshold signals when replacement outpaces repair economics

https://sacramento-precision-hvac-affordable-sac-sac-ca5294.zenbloomer.com/posts/thermostat-settings-at-78-80degf-during-work-hours-extend-system-lifespan-beyond-aggressive-cooling-cycles

The ideal age to replace an HVAC system hinges on documented cost-ratio data: once repair expenses exceed 50% of replacement cost in a single season, replacement becomes the data-backed threshold