Replaced all ten smoke detectors in the house, with two of them being combo smoke/carbon monoxide detectors.
These ones have built-in batteries that are supposed to last 10 years, so hopefully no more chirping detectors in the middle of the night.
For those of you that might not know this, the detectors should be replaced every 10 years, as the sensors wear out. Newer ones will chirp when the sensors start to go out, but older detectors may not. If your smoke or CO detectors might be more than 10 years old, then it would be advisable to replace them. If you're not sure, then take one down and check if there is a date of manufacture on the inside.
Amazon is running a promo on Kidde products this month, "Buy $100, get $20 off". I ended up placing three separate orders for the various detectors, with each order getting $20 off, so saved $60 total.
Since it didn't take too long to replace them, I also took apart the jetted tub enclosure to replace the shower wand hose that was broken.