To further represent the scarce nature of Special and Rare choices there is a limit on how many duplicates of each unit you can include in your army. Remember, this limit applies only to duplicate Special or Rare unit choices, not to the total number of Special and Rare units overall. Note that this limit applies to the basic unit type and isn't dependent on the size of the unit or optional wargear. If a character has a, , or mount that is available as a Special or Rare choice, then these will also count towards the limit of duplicate choices.
Example: if you play a 2500 points game; you may choose three of the same special unit in your army, but only one of each rare unit. At 3000 points, you may choose up to four of the same special unit, and two of the same rare unit.