What would entice you to work on someone else's game?

It's something that I've been thinking about recently. On account of my lack of spriting ability, some point along the line I'm probably going to need an artist to design new enemies, for example. But what would a spriter require from a project before they would want to work on it?

We'll have to assume that motivation would be purely intrinsic, as a lot of people are only making RPGs for fun (and hence couldn't/wouldn't pay for an artist's work). Would the project have to be a decent way through, with a good amount of content to see? Or would an early project that takes a spriter's interest be better?

I'd love to hear from people with experience here, particularly artists/musicians/anyone who has worked on somebody else's project.

Preferably, the project should have a chance at finishing

Preferably, the project should have a chance at finishing

People like it if you've already completed a game. They find that you have an understanding of what it takes to make a game, and are more likely to join you.

that too