Short answer
Only 4 of 53 watches here have a published update promise, from 3 to 5 years. The rest are 'not published'.
Samsung Galaxy Watch9: 5 years. Samsung spec page (UAE store, same model): 'Security Update Period (Valid until) 31 July 2031' — security updates, about 5 years from the July 2026 launch; the US page does not list it
Samsung Galaxy Watch Ultra2: 5 years. Samsung spec page (UAE store, same model): 'Security Update Period (Valid until) 31 July 2031' — security updates, about 5 years from launch; not on the US page
Google Pixel Watch 5: 3 years. Google support table: software updates 'until at least' October 2029 for Pixel Watch 5 (released October 2026) — 'at least 3 years'
Google Pixel Watch 4: 3 years. Google support table: software updates 'until at least' October 2028 for Pixel Watch 4 (released October 2025) — 'at least 3 years'
Apple, Samsung, Fitbit, OnePlus, Garmin, Amazfit, COROS, Suunto, Polar, Withings publish no update period for the watches here. Several keep updating watches for years, but a buyer has no promise to hold them to, and this site does not guess one.
Everyday smartwatch · Wear OS
Best for: Samsung Galaxy phone owners who want a light everyday watch with full health features
Rugged outdoor · Wear OS
Best for: Galaxy phone owners who trail run or hike and want multi-day battery on Wear OS
Everyday smartwatch · Wear OS
Best for: Android owners (any brand) who want Fitbit-grade health tracking on Wear OS
No watch here needs a subscription to work. 41 of 53 come from makers that sell an optional paid tier; what it gates ranges from video classes to coaching and deeper analysis.
Because the headline is measured with the screen asleep between glances. Where makers publish both figures, turning the always-on display on leaves a median 39% of the headline in this catalog, and a GPS workout drains faster still.
Every specification explained, with the real numbers from the catalog behind each one.