Should I charge my kid for gas and equipment?

It feels petty, which is why most families never do it. Your kid is thirteen, the gas is four dollars, and charging them for it sits somewhere between unnecessary and mean.

Here is what happens if you do not. Your kid mows a lawn for thirty dollars and believes they made thirty dollars. The gas, the trimmer line, the bags, and the wear on a mower somebody else bought are all invisible, so profit and revenue are the same number in their head. That is the single most common misunderstanding in a first business, and it is the thing the whole margin lesson is built to fix.

Once they pay for something, the arithmetic changes shape. Thirty dollars in, four dollars out, twenty six dollars actually earned. It is a small difference and it rearranges how a kid thinks about a price, which is why Sophie's line about making your money when you buy is the hinge the book turns on.

Timing matters. Do not charge for anything on day one, because the point of the free test is that nothing costs money until a customer has said yes. Start once the business is earning regularly, and say why: from now on the business pays for what the business uses.

Keep it simple enough that it does not become an accounting exercise. A flat few dollars a job for fuel and consumables is fine. Metering actual usage teaches nothing extra and turns a good lesson into a chore.

Family equipment is its own question. Charging rent on a mower you would own anyway is a stretch. A contribution toward maintenance is not, because the business genuinely is wearing it out faster. A fixed amount per month that goes toward the eventual service is honest and easy to explain.

Two things to avoid. Do not make it retroactive, because a bill for the summer that already happened reads as a trick. And do not quietly take it out of what they earned. They pay it, deliberately, from their own money, because the noticing is the entire point.