Board Thread:General Discussion/@comment-25926288-20150622205208/@comment-24674051-20150623141640

I think one thing that limits magic is Rumple's favorite Mantra - "all magic comes with a price."

There is some cost to ANY magic, we just don't always see what that cost is. Blue is obviously magical, but she rarely uses magic (other than simple fairy magic), and it seems that the few times she does it is with a slight reluctance.

Potioncraft, on the other hand, seems to be less costly. And they've used it several times (Regina & Rumple with forgetting potions, King George and Regina with Infertility potions, Rumple with all of his potions, including True Love,  Maleficent with sleeping potions. and so on.)  Also, Potioncraft seems to be usable by people with less or even no magic. Belle has made a couple of potions.

I envision the spells that use vocalized incantations as being extremely powerful (and probably extremely costly). The only ones I remember are Regina with the Dagger and Hat (Rumple and Blue can just hand wave, but others have to go full on incantation), and the Apprentice when he is dealing with Darkness (Both early with Emma/Lily, and with Rumple).