What battery life should I look for?

For most weekly riders, 15–20 hours of real-world battery is plenty. Long-distance and bikepacking riders should look at 30+ hours, and reviewers consistently flag the Wahoo Roam V3, Edge 540, and Wahoo ACE as strong on endurance. Note that several reviewers report real-world battery life on bright-touchscreen flagships (Edge 850, ACE) falls well short of advertised numbers.