She's just trying to 'earn a living'. [=to earn the money needed for food, clothing, etc.]
He will do anything to 'earn his keep'. [=to earn what is needed to support himself]
He 'earned/won his spurs' by doubling the company's profits in the past year.
(..) when you're younger. I don't know. Someone who wants kids. Likes kids. Wants kids. Healthy enough to play with his kids. Please let him earn more money than I do. You might not understand that now, but believe me, you will one day. Otherwise, that's a recipe for disaster. (..)2009 Up in the Air
(..) and a full year of placement services through our company, CTC. Placement services. That's generous. Commonly, it takes one month of searching for every $ you expect to earn in salary. So, I could be looking for a while. -Not necessarily. -Don't even sweat it. I'm pretty confident about my plans. (..)2009 Up in the Air