I have had a Garmin Forerunner 255 for about eight months now. Before that I used my phone for everything, step counting, run tracking, sleep, whatever. The phone was fine. It was also constantly dead at the wrong moment and I got tired of carrying it on every run.

The watch is not perfect. It does about fifty things I do not care about and maybe five I actually use. Here are the five.

Smartwatch on wrist
The watch face I actually use. Not the one with twelve data fields.

1. GPS Run Tracking

This is the whole reason I bought it. I press one button, I run, I stop it, I get a map and pace splits. That is it.

The accuracy is good enough. I run the same loop along the rambla in Montevideo almost every time and the GPS trace is consistent, maybe 3-4 meters of wobble on the waterfront section where the buildings are close. On open road it is spot on.

Battery during a run barely moves. A one-hour run takes maybe 5-6 percent. My phone would lose 15 percent doing the same thing with Strava open.

2. Training Readiness Score

Smartwatch product shot
Looks complicated. Most of these metrics I ignore.

Every morning the watch gives me a number from 0 to 100 that says how ready I am to train. It uses sleep, HRV, stress, and recent training load.

I do not follow it religiously. But when it says 35 and I feel fine, I go easy, and usually by kilometer 3 I realize it was right. When it says 85 I push harder. It is a useful sanity check, not a coach.

The HRV measurement overnight is the part I actually trust. When my HRV drops 10 points below my baseline I know I am either getting sick or I drank too much wine the night before. It is never wrong about that.

3. Sleep Tracking

I know sleep tracking on wrist wearables is not lab-accurate. I do not care. I wanted trends, not precise REM minute counts.

The trends are useful. I can see that I sleep worse when I eat late, that I get more deep sleep when I run in the morning, and that my average sleep dropped when I started working on a project with a 4-hour timezone difference with the UK. The number itself is not perfect but the pattern is real.

4. Interval Workouts

I used to time intervals on my phone with a janky app that would lose focus and stop beeping. The watch does it natively.

Here is the setup I use for 400m repeats:

Workout: Intervals
Type: Run
Warmup: 10 min easy
Repeat 6x:
  Run: 400 m, target pace 4:30/km
  Rest: 90 sec
Cooldown: 10 min easy

It vibrates at each transition. I never have to look at the screen. The lap pace shows for each interval in the summary afterward. Simple, and it works every time.

5. Body Battery

Person running outdoors
Running along the rambla. The watch does the tracking, I do the suffering.

This is a score from 0 to 100 that supposedly represents your energy reserves. It goes up when you sleep and down when you are active or stressed.

It sounds like pseudoscience and maybe it is. But after eight months I can tell you it correlates pretty well with how I actually feel. A Body Battery of 20 means I am going to have a slow day. A 90 means I should go do the long run I was planning.

I do not make decisions based on it alone. But I check it every morning and it has been right more often than my own assessment of how I feel, which is annoying but true.

The Stuff I Ignore

The watch has a lot of features I do not touch: