Battery life in the wearable world is even more of an issue than it is with phones. You want us to charge a smartwatch every day? Are you for real?
The situation is much less upsetting with fitness trackers, but that comes at a cost to functionality. You need to keep a close eye on what you'll actually get when you're out for a new band.
Our minimum is a week's use – and we mean active use, not a week kept in a drawer. And when using GPS we want at least a marathon's worth. We're not talking a sub-three-hour superhero marathon either, but a solid six-hour 'semi-reformed couch potato' marathon.
The kings of this sort of stamina are real runners' watches. The Garmin Fenix 3 lasts for 20 hours of GPS or a good few weeks as a pure watch. Even the slim Garmin Vivoactive lasts for 10 hours of GPS. On the naughty step, the Fitbit Charge only lasts five hours of GPS goodness.
The latest bright hope for future band battery life comes from Samsung. In late 2015 it unveiled a 0.3mm-thick bendy battery that can live in a watch's strap, which would solve a lot of these issues.