The Forerunner 405, 405CX, and 410 have two internal memory limitations: 20 hours of tracks and 1,000 laps.
20-hours of Track Log Data
A track can be described as points the GPS records containing vast amounts of information, i.e., speed, location, elevation, and time, while performing a workout. Once the track log is full, the newest track points will replace the points from the oldest workout. Once the tracks are replaced, the workouts will only contain summary data, which consists of speed, distance, and time.
Each workout is considered one lap unless the Lap button was pressed during a workout to create additional lap(s). A Lap Database Almost Full Delete Oldest alert appears as the memory is close to becoming full. When full, the device will no longer record workouts until either transferred to the computer or deleted from the watch. Workouts can be deleted from the History menu.
Garmin Connect accepts workouts from the Forerunner 405, 405CX, or 410 to save to the computer.
Garmin Connect - http://connect.garmin.com/