How accurate are sleep trackers? Should you rely on them?

The booming coffee industry suggests that many people aren’t bursting with natural energy. Most experts agree that one culprit behind our collective exhaustion is poor sleep. In response, the biggest names in tech —including Fitbit, Garmin, Apple, and more — offer tools to help users build better habits. But how accurate are sleep trackers? Can a device help you improve your sleep? We break down what you can and cannot expect from these potential bedmates.

Do sleep trackers actually work?