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.
"Maybe you're cursed?" the girl says, hesitantly. "If there was a strange old man involved, and you can't get rid of it at all..."
Kicking her legs. "Do you wanna learn Heartful magic then?"
She jumps down.
"It's about wanting stuff, specifically enough and in the right way that it happens! Some stuff, like lighting a fire, is really simple and easy to do, while some stuff's harder. I started with meditating on wanting my fire lit - it was cold and I wouldn't get a fire otherwise."
"Yeah. Though so are things you want a lot, and things you can clearly visualize."
"I dunno! I can make people immortal, if I care about them. Not myself, but that's 'cause I'm Harrowed. I can light fires and make things and heal people, and I've heard stories of devoted lovers bringing back the dead..."
"Yeah. I think there's an effective cap, just on how much people can care..."
"Hmmm." She kicks her legs. "I think it's a little different for everyone. You gotta be focusing on just that to get it started? Gotta want just that thing at the moment."
"What's something you tend to want? That's small? We can start with that."