Board Thread:Dragon City Questions and Answers/@comment-41.129.123.54-20130514131634/@comment-3271569-20130514151519

You will always need gold and food to feed your dragons so it's indeed an good idea to place your island full with legendary dragons. However if would keep the followings things:
 * Don't sell your habitats, place them in your storage
 * Leveled, Unique and Exlusive dragon should not be saled, place them in the Dragonarium.
 * I would keep the pures or place them all in the dragonarium and the habitats in the storrage, since it's possible your will need them in the future.

Like I said before, social point is planning something big ;)