The Garmin Enduro 3 finished Val d'Aran UTMB — 111.6km, 6,060m of elevation, full GPS navigation — with 60% battery remaining. Charge interval in real-world heavy use: every 2–3 weeks. With solar charging, net battery loss on full outdoor days can be zero.
In six years across four continents and multiple UTMB-level races: zero technical failures. The watch is infrastructure, not equipment. You wear it and forget it exists, which is exactly what you need when you're 80km into a race.