If you need some motivation to get active, the Fitbit One will do the job. It tracks your steps, sleep and calories, and it's cheaper than its main rivals, including the Nike+ Fuelband SE.
The One also has an altimeter, which means it will reward you for climbing stairs instead of taking the lift. Unlike trackers without an altimeter, you'll see a higher calorie count when you use the Fitbit One.
The display doesn't show 'Active minutes' which you get on the Fitbit Force, but this is still tracked and displayed in the free companion app, and also on Fitbit's website.
It's most convenient when you have a smartphone, as data can be synching automatically all day (you'll need a supported Android or iOS device with Bluetooth 4.0 or later) but you also get a Bluetooth USB dongle in the box to sync wirelessly with a desktop PC, laptop or Mac.
There's also a fabric wristband in the box so you can wear the One at night. This can track when you fell asleep, and will tell you how long you slept, how many times you woke and how restless you were. A vibrating motor lets you set silent alarms to gently wake you in the morning.
Our only criticism of the One is that it needs a proprietary charging cable - if Fitbit had used a standard microUSB port, there would be no problems sourcing a replacement cable if you lose it.
However, overall, the Fitbit One is a superb activity tracker and earns our Recommended award. See also: full Fitbit One review.