How Long Do Google Nest Protect Smoke Alarms Usually Last?

There are plenty of common problems with Google Home devices. Yet, these largely don't apply to the Google Nest Protect smoke and CO alarms, which, according to many, work well. Though it was discontinued in 2025, there are plenty of these Nest Protects still in use, which may leave owners wondering how long they're expected to last.

The answer varies, depending on the lifespan of the smart alarm and the reliability of the device itself. The second generation Nest Protect lasts 10 years from the manufacturing date: Not the date you activated it, but rather the day it left the factory. This is a typical timeframe for smoke and CO sensors to reach the end of their useful life. Three months before it goes bad, your Nest Protect will send you a push notification, and if you don't replace it after the expiration date, the alarm will start chirping continuously.

It's unfortunate that the Nest Protect has joined the ranks of the discontinued Google Chromecast because judging by the online discourse, they were pretty reliable. Save for complaints about a shorter 8-year lifespan in some instances, for the most part, users are disappointed about the discontinuation. One unhappy Redditor had multiple Google Nest Protect units for 10 years and noted they all performed flawlessly.

Just because Google killed off a product doesn't mean you can't find one that is still sealed floating around online. On eBay, there are new Nest Protect devices that will work as intended until the 2030s. Make sure to confirm the manufacturing date to see how much time you have to be on the safe side though. 

However, there is a catch: Sealed Nest Protects can be expensive, with some listed for up to $200. If you want to switch camps, there are plenty of highly-rated smoke alarms for smart homes that work as a solid alternative to the Google Nest Protect. For example, the X-Sense SC07-MR projects sound at the standard 85 dB at 10 feet, and for an extra $4.99 per month, you get 24/7 professional monitoring. It costs $46, woks with a smart app, and is compatible with Home Assistant.