Two separate businesses works better than one shared, because the point is owning something and a shared thing is nobody's. Within two years they can work the same week together. Three or four years means same material at different speeds. Five or more is effectively two separate projects. Watch for comparison, and measure each kid against where they started rather than each other.
Two separate businesses works better than one shared one, and the reason is that the whole point is owning something. A thing two kids share is nobody's.
How much they can run in parallel depends on the gap.
Two years or less. They can work through the same material at the same pace, read the same chapter in the same week, and talk about it. That comparison is genuinely useful, and a little competition between them usually helps rather than hurts.
Three or four years. Same material, different speeds. The younger one will need more of you and the older one will move ahead. Workable, as long as nobody is being held to the other's pace.
Five or more. Effectively two separate projects that happen to be in the same house. An eight year old and a fifteen year old are not doing the same thing in any meaningful sense, and pretending otherwise usually means the younger one is lost or the older one is bored.
The thing to watch is comparison. If one kid gets customers faster, or earns more, that will be visible, and at these ages it lands hard. Two things help: different businesses, so there is no direct scoreboard, and measuring each kid against where they started rather than against each other.
Practically, they can share the novel and the parent material. They cannot share a workbook, which is written in, or consumables, which get used up.
One honest thing. Kids at different ages need different amounts of you, and the younger one will take more. That is worth planning for rather than discovering in week three when the older one has quietly stopped because nobody noticed.
Five questions about age, budget, time, and what they actually like doing. Four matched ideas at the end, free, with no email needed to see them.
Take the quizA kid who cuts, edges, and cleans up usually starts between $25 and $40. Professionals charge about $30 to $85 a visit, and a young founder starting below that is being paid less for being unproven, not for being young.
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What should a kid charge to mow a lawn?Ten people who already know them, one prepared sentence, and an easy way for each of them to say no.
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How does a kid find their first customer?Less than almost anyone expects, and for a lot of these ideas the honest answer is nothing until somebody has already said yes to a price.
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How much money does a kid need to start a business?Earlier than most people think, as long as the business matches what the kid can actually handle. The limit is rarely age itself.
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What age can a kid start a business?A program from Founder's Best Friend. Built for kids 8 to 18 who want something of their own.