Once HVAC equipment hits 15 years old, failure costs spike beyond $5,000 annually
https://precision-hvac-repair-sac-apartment-sac-near-liahona-chapel3145.scriblorax.com/posts/sacramento-ac-breakdown-triage-steps-to-save-25-on-repair-costs
The $5,000 rule is a failure-risk threshold: once your HVAC system reaches age 15, running it beyond that point exposes you to replacement-cost shock far exceeding $5,000, plus the breakdown liability of a mid-cycle failure during Sacramento's