I currently have hard wired smoke detectors with 9v battery backup that front loads without need to remove the detector.

It’s as convenient as it can be to replace the battery.

They now all over 10 years old and due for replacement.

It seems that new detectors have lifetime batteries. At first that seems more convenient to not have to keep replacing batteries, but what happens if the battery goes low at 3AM, 9 years from now? You can’t pop in fresh batteries go back sleep and replace the unit later.

Has anyone here owned these when they reached the end of their lives?

Can you silence the low battery warning for days so you have time to order and install replacement detectors?

Do they have any warning lights that will warn you the battery is starting to get low so you can order replacement detectors before the annoying beeping starts?