For a ladder to be successful, its members need to play fairly regularly and be active.
There is a point penalty for inactivity, if a player does not play at least 1 match in a period of 60 days, they will lose 50 points. If a player is inactive for 90 days, they will be removed from the ladder.
If you are unavailable to play (e.g.: injury, holidays), you can set up your unavailability on your profile, this way your idle timer will be paused and you will not lose points.