The Forerunner 910XT's memory limit depends on a number of factors, such as what type of sport the device is in, the accessories it is paired with (heart rate monitor, foot pod, GSC 10, or power meter), and the current training settings. Below is a list of approximate hours to expect with different accessories and recording methods:
The 910XT will automatically overwrite the older workout data once the memory becomes full. A warning will appear once the memory is almost full to allow time to transfer workouts to the computer or delete specific activities. Workouts can be deleted in the History menu or transferred to Garmin Connect.