The Garmin Lap feature is a useful tool that you can set to automatically lock in your pre-defined position so that you can accurately track how many laps you have done over a course without having to push a button. This way you can set a specific position as your lap starting point and it will keep track of it for you and increment an additional lap every time you have passed this point. Just be sure you enable Auto Lap in your settings all its all done for you.