My HVAC is 25 years old and going strong. Only quirks it has is the airflow sensor needs to be blown (haha) once in the winter. Only maintenance outside of the usual I’ve done is replace the fan capacitor.
My water heater is about 10 years old but one of the perks of my gas utility is a water heater warranty so when it comes time to replace or repair part of the cost will be covered.
A family friend in a similar spot just referred to each other as “life partners”. Any others it was just “partner” or “significant other”.