How do you know when it's time to leave a team?

Software engineers all change teams or jobs every so often. Sometimes it's for personal reasons, sometimes it's for compensation, location, etc.

What about when there's no clear self-interest or benefit in changing teams? How did you know when it was the right time? The specific case I have in mind is leaving one team in BigCo and joining another team in BigCo, but the same is applicable in many other situations as well.