Habitat

NOTE: Some Habitats need help from your friends in order to be opened, like other buildings, as the Stadium. If you can afford (or don't have any friends), open them with Gems.

Habitat Optimization
As you know, there is only so much space on all of the islands to fit in all your habitats, Hatchery, Breeding Mountain, etc... That being said, this are is for brief speculation on your idea of the best habitats to have. For example, having 12 Large Dark Habitats wouldn't do you any good because you would only have one Dragon in each, so it would be wasted, but 1 Large Earth, 4 Large Fire, 4 Large Water, 2 Large Plant, 1 Large Electric, 3 Large Ice, 2 Large Metal, 3 Large Dark and 4 Legendary would give you a spread on everything. For the sake of the argument, stick to 28 Habitats max, since for 5 levels that is the max. Feel free to add.