New Delhi, Oct. 19 -- Would you rather check your health data on a ring you barely notice or wear a watch that puts fitness stats, calls and notifications on your wrist? Both of these devices can help you understand your daily activity, but they serve different purposes. Choosing between them is less about which wearable has more sensors and more about what you expect it to do. Smart rings appeal to buyers who want health insights without another screen to check. Smartwatches, meanwhile, combine fitness tracking with features that can make a difference throughout the day. Before spending your money, here is what to consider, from overnight comfort and battery life to phone compatibility and long-term value.

A smart ring packs sensors and...