Fitness Trackers and Smartwatches: What Actually Matters
Wearables list dozens of sensors, but only a few change your daily experience. Here is how to choose a fitness tracker or smartwatch without overpaying for features you will never open.
Decide: tracker or smartwatch
A slim fitness band focuses on steps, heart rate, and sleep with multi-day battery and a low price. A full smartwatch adds apps, contactless pay, and rich notifications but needs charging every day or two and costs more. If you mainly want activity and sleep data, a band is lighter, cheaper, and lasts longer.
Battery life is the quiet dealbreaker
The best wearable is the one you actually keep on. Bands running a week or more get worn through the night for sleep tracking; daily-charge watches often come off at bedtime. Match battery life to whether sleep data matters to you.
Accuracy where it counts
Wrist heart rate is good for trends and steady cardio but less reliable for intervals; a chest strap still wins for serious training. Built-in GPS matters if you run or cycle and want pace and distance without your phone. Sleep stages are a useful trend, not a medical readout.
Ecosystem and subscriptions
Check whether the companion app locks key insights behind a subscription, and whether the watch pairs cleanly with your phone. A watch that fights your phone gets abandoned fast.
What optical heart rate gets right and wrong
Wrist-based optical sensors shine light into the skin and read reflected changes in blood volume. They are accurate to within a few beats per minute for resting heart rate and steady-state effort, which covers walking, easy running, and sleep. Where they degrade is rapid change: interval work, sprints, and heavy lifting all produce lag and occasional cadence lock, where the reading latches onto your arm swing instead of your pulse.
If your training is steady cardio, a wrist sensor is fine. If it is intervals or strength, a chest strap paired over Bluetooth remains substantially more accurate, and most trackers accept one. Skin tone, tattoos, and strap tightness all affect optical accuracy, and a loose strap is the most common cause of bad data.
Sleep and recovery scores, calibrated honestly
Sleep staging from a wrist device is an estimate built from movement and heart rate variability. Compared against clinical polysomnography, consumer devices are reasonably good at distinguishing sleep from wake and considerably weaker at separating light, deep, and REM. Total sleep time and consistency are the numbers worth acting on. The stage breakdown is directional at best.
Recovery and readiness scores combine resting heart rate, HRV, and sleep into a single figure. The absolute number means little, and the trend means a lot. A readiness score that drops three days running is a real signal even if 68 versus 74 is not.
GPS: built in, connected, or none
Built-in GPS records distance and pace without your phone, and it is the feature that separates running watches from step counters. It costs battery, typically dropping a device from days to 8 to 20 hours of continuous tracking.
Connected GPS borrows the phone's radio, which is accurate and free of battery cost on the watch but requires carrying the phone. For gym and walking use it is entirely sufficient.
Dual-frequency GPS, sometimes listed as multi-band or L1+L5, is the meaningful recent upgrade. It substantially improves accuracy in cities and under tree cover, where single-band traces wander across buildings. If you run in a downtown or wooded area, it is the spec worth paying for.
Subscriptions, and what they gate
Several major brands now put the analysis behind a monthly fee while leaving raw data free. Before buying, check exactly what stops working without the subscription. In some ecosystems it is advanced insights you will not miss. In others it is the sleep score and the training guidance, which is most of why you bought the device.
At $70 to $120 a year, a subscription over three years often exceeds the hardware cost. That belongs in the price comparison, not outside it.
What a good price looks like
Basic bands list $50 to $100 and fall to $30 to $60. Mid-tier trackers with built-in GPS list $150 to $250 and reach $100 to $170 at sale events. Full smartwatches run $300 to $500 and drop to $200 to $350, with the steepest discounts on prior-generation models right after a new launch. That is the strongest value in the category: last year's flagship at 40 percent off is a better device than this year's mid-tier at full price, and the sensor hardware rarely changes much year over year.
Compare current picks
See tracker and smartwatch deals in our fitness and tech categories, and check battery and GPS details in the price context before buying.