Until the early 21st century, tracking your fitness meant using a stopwatch, charting your progress on graph paper, and, if you were devoted, walking around with a small box chained to your hip. Nowadays you pretty much have to ask your smartphone not to track your steps, and McDonald’s recently gave away step trackers in Happy Meals (until they gave kids rashes).

We currently cover three types of devices that can keep you informed about how much you’re moving and push you toward your fitness goals: GPS running watches, fitness trackers, and smartwatches, both for Android and iPhone. They all perform three basic functions:

• Track your day-to-day activity (steps, flights of stairs, increased-heart-rate work, sleep)
• Measure your distances in running, biking, hiking, and other outdoor activities
• Alert you to phone calls, notifications, and alarms from your smartphone

We’ve previously answered a reader question about smartwatches versus fitness trackers. But these devices keep adding features and getting smaller, and their makers are increasingly selling them as all-in-one solutions. After a discussion among Wirecutter editors who have tested and researched these devices, we concluded that a true all-in-one doesn’t yet exist. All three devices do all three tasks, but each of them can only do one task really well. Although it’s tempting to say, “I want it all!” and opt for a “fitness smartwatch” such as the Garmin Vívoactive or Fitbit Surge, in our opinion these devices are not yet great choices for most people. They’re more expensive than a fitness tracker, they’re much bulkier than you might expect, and they don’t excel at any one task. So it’s best to pick one main priority and stick to that. If you’re not sure where you stand, here are three questions that can clear things up.