earn (one's) keep
earn (one's) keep
To perform sufficient work or help in exchange for money or housing. If you're going to live here rent-free, then you need to earn your keep by helping out with the cooking and cleaning. That boarder earns his keep by doing maintenance in the building.
earn one's keep
to help out with chores in return for food and a place to live; to earn one's pay by doing what is expected. I earn my keep at college by shoveling snow in the winter. Tom hardly earns his keep around here. He should be fired.
earn one's keep
Also, be worth one's keep or salt . Work well enough to deserve what one is paid, as in Get a job-it's time you earned your keep, or With that batting average he's not worth his salt. The keep in this phrase refers to "room and board," which in former times sometimes constituted the only reward for working (on a farm, in a home, etc.). The salt stands for "salary" and alludes to the ancient Roman practice of paying soldiers an allowance to buy salt. [First half of 1800s]