Maximum DIN refers to the highest DIN setting of the binding. The DIN range that works best of you will be primarily determined by weight and ability, meaning larger or more advanced skiers need higher DIN settings than lighter or less aggressive skiers.
Max DIN 2.5 is for youth skiers only that are under 65lbs.
Max DIN's 4, 4.5 are for youth skiers only that are under 90lbs.
Max DIN's 7, 9, 10 are for teen and intermediate skiers under 150lbs.
Max DIN's 11, 12, 13 are for advanced teens and intermediate to advanced adults less than 190lbs.
Max DIN 14 is for intermediate skiers over 190lbs or advanced/expert skiers 150-210lbs.
Max DIN's 16, 18 are for advanced to expert skiers over 180lbs.