Regularly syncing your Nike+ device to your computer's USB port ensures that your workout data does not fill your device's memory.
The devices that require syncing data to your Nike+ account via Nike+ Connect include the Nike+ FuelBand SE, first generation FuelBand, Nike+ SportWatch GPS, Nike+ SportBand, Nike+ Basketball and Nike+ Training Sport Sensors, and Nike + iPod Running Sensors.
Although your device can store 1-3 months of activity data, Nike recommends syncing three times per day for best results. If your device's memory is full, you will not be able to record workout data until you sync your device to your computer.
Plugging your device into your computer's USB port also charges your device. Avoid recharging your device with car or wall chargers. These types of chargers lack a clock or calendar setting and, in some cases, can lead to date errors on your workout data.