Source: Google
In the markets where Google's Sleep Sensing feature is available, it'll remain free for an extra year. Initially, Google planned to integrate the feature built into the Google Nest Hub 2nd-gen into Fitbit Premium this 2023. But now, on its product page, it mentions that the sleep tracking will be "free of charge through 2023." The company is likely to work on improving the feature before charging for it. So, you can hold off on that Fitbit Premium subscription if you haven't subscribed yet.