not the parent, but when my nest protects died i switched to dumb ones. all co2 detectors expire after ten years, nest decided the appropriate action is to just brick it when they were ten years old. the only feature i really used was using the app to silence it when cooking got smoky. but theres very few options for smart ones, lack of interconnect compatibility got frustrating if i wanted to mix smart and dumb, and it would have easily cost twice as much(i have 6 detectors).

ive considered connecting the interconnect wire to my esp32 (that replaced the security system) and get it pushed into home assistant, but without the ability to silence, a push notification that it is going off just didnt seem worth it

Meanwhile my mercury-bulb thermostat from the 1960s still works perfectly.