The best chores for kids by age are visible, manageable, and repeated often enough to become familiar.
Start with obvious, repeatable tasks
Children do better with chores they can see and understand: toys away, dishes to sink, towels hung, shoes away.
Increase independence slowly
As children grow, move from short visible chores to more independent resets and room care.
Keep the interface age-appropriate
The best chore system for kids should keep the child-facing experience simple, even if the adult system behind it is more complex.