Good to know! We bought a few with integrated 10-year batteries from Home Depot a few years back, but I didn't realize you could get regular lithium 9Vs that last that long in a smoke detector now.
!! even the hard-wired ones are supposed to be replaced after 10 years, and new hard-wired ones will automatically brick themselves after the 10 years is up !!
For anyone reading this wondering how that's safe, I believe they make noise regularly once they reach this state, to encourage you to replace them, rather than just silently failing to operate!
