Select Setup > Recording > Advanced Setup > Auto Save.

When Full

Automatically saves the current recording and starts a new one when the current recording is near 20,000 track points.

Daily

Automatically saves the previous day's recording and starts a new one when you turn on the device on a new day.

Weekly

Automatically saves the previous week's recording and starts a new one when you turn on the device on a new week.

Auto

Automatically saves the current recording based on its length and the number of track points taken.

Never

Never saves the current recording automatically. When the current recording nears 20,000 track points, the device filters the active track to remove redundant points while retaining the shape and history of the recording. Unfiltered points are saved in a temporary GPX and FIT file that is saved or discarded when the recording stops.

NOTE: When importing FIT activities or GPX tracks with more than 20,000 track points, the device filters the line to fit in the device memory and improve map drawing performance, while retaining the shape and history of the recording. The FIT and GPX files retain all of their original track points.