Just as aside, lithium-battery powered smoke detectors are a godsend. The battery lifespan lasts the recommended life span of the detector, i.e. around 10 years. No battery replacements needed, although you still ought to test them once in a while.
However one downside is that they also can't be turned off (by design) and the hush function on the ones I've tried (two models, both from Kidde) has been defective. No matter if I repeatedly press it, hold it, it doesn't care. It says hush mode then immediately blast again.
I destroyed the first one because it was night time and I have neighbors. Now I put them in the freezer. Next time I'll get another brand!
Probably a wise choice. In Wirecutter's review of basic smoke alarms they have this to say about Kidde:
>> With placement on the shelves of Home Depot, Kidde is the most prominent competitor to First Alert. Their most up to date line of smoke alarms is called Detect and they have models with features similar to the recommended First Alerts. The downside is that Kidde's overall track record is, in a word, disturbing. In 2021, the company recalled 226,000 smoke and combination smoke/CO alarms. In 2018, they recalled more than 450,000 dual-sensor smoke alarms. In 2016, another recall involved 3.6 million smoke/CO alarms. In 2014, another 1.2 million smoke and smoke/CO alarms were recalled. In addition, since 2005, Kidde has enacted four separate fire extinguisher recalls of 470,000 units (2005), 167,000 units (2009), 4.6 million units (2015), and 37.8 million units (2017). In early 2021, a federal judge ordered Kidde to pay a $12 million civil penalty “in connection with allegations that the company failed to timely inform the Consumer Product Safety Commission about problems with fire extinguishers manufactured by the company.” For these reasons, we can’t in good conscience recommend any Kidde products to our readers.
>> Although First Alert is not immune to recalls (it recalled nearly 150,000 smoke alarms and combination smoke/CO alarms in 2006 and roughly 600,000 fire extinguishers in 2000), none of them are recent or on the scale of what Kidde has had to do.