When I bought this house seven years ago this month, it came equipped as per code with a smoke detector in every room, plus, a CO2 detector in the main living area. It just so happens that the room's smoke detector is right next to the CO2 one. Now, maybe two/three years back, I replaced the basic smoke detector with a nicer one with wifi built in, so that if it went off it would text my phone, turn on the lights, alert other devices, etc. It also happens to also detect CO2 on the side, so it's a bit redundant, but it came with that built in, so whatever.
Tonight, the CO2 detector started to chirp. I figured it was a low battery, but, when I pried it off an looked at it, the sequence of chirps was actually signalling "end of life", the CO2 detector bits inside are only good for seven years, and now I need to buy a new one. There's a little timer inside that waits seven years from the first time it powers on, then signals time to be replaced. Of course, this happens exactly at 6:01 PM when Home Depot just closed for quarantine restricted hours and every other store is closed too.
So, I get a chair from the other room, climb up, pull down the CO2 detector, yank the batteries to stop it from chirping, drag the chair back to the other room, and sit for a good six or seven minutes, when... of course... *chirp*!
The smoke detector batteries also happened to run out after however long they've been in there, maybe a year... within ten minutes of the seven-year end of life cycle on the detector right next to it.
So I had to get the chair back out, climb up again, and yank that one down and replace the batteries and put it back up. (At least, now, it is silent and the app reports all is well... for a brief moment I wondered if indeed I had a CO2 leak because both detectors started making noise at the same time...)
What are the odds?
I guess if I show up here alive tomorrow, it's just a really, really unlikely coincidence and not a CO2 leak...