The constraint is always raw material. She has no shortage of ideas or time in which to put them into practice. Hence, she is most avaricious in acquiring hearts whenever an opportunity presents itself. Having a stockpile means she need waste as little time as possible.
"I did not lose them, I know precisely where they are. The ability to use them was taken from me."
"Aw. Someone made you have a heart? That's mean."
"Yes. An old man with a staff."
"Old men with staffs and old ladies with weird voices do all the cool stuff in the stories," she says, sagely. "Or at least the human stories."
"If you say so. I never paid much attention and they're too stupid to write anything down."
"They've got really good memories instead, I think! The one who taught me magic knew all sorts of stuff, from her whole life."
"It's good magic. I can turn into things, now!"
"How nice for you."
"If you don't like your heart, have you tried taking it out?"
"I'm given to understand that usually has poor results."
"You can do it safely! Some humans do it on purpose, even."
"Can I use my artifacts again if I do that?"
"I think so! Heartless humans can, at least."
"Do you know how to safely remove a heart?"
"I've done it to someone before! Though I think it's safer if you do it yourself. The thing I heard was focusing on really wanting it gone for, like, a few minutes?"
She'll try that, then.
She doesn't want this thing in her chest, it should be gone, her life was better before it, if she gets rid of it the old man loses...
The girl's frowning, kicking her legs and biting her lip.
Get this damn piece of shit out-
Still not doing anything, except maybe giving her indigestion.
Out out out out out get out! She doesn't want it! Useless! Worthless! A chain dragging her down that she will snap!
Her chest hurts, sharp and bitter, and she's becoming more vibrant, possibly, her heart beating loud in her ears like it's grown a size larger -
What the fuck! This is the opposite of what she wants to happen! She wants silence, not a louder heartbeat!
Her heartbeat speeds up but doesn't grow much louder.
Fine. Fuck this, then.