An age recommendation is a useful starting point, but it does not tell the whole story. Some children seek movement; others prefer building, imagining or solving problems.
Organise the range by play style as well: active, creative, constructive, imaginative or social. This helps parents and gift buyers find something that genuinely suits the child.
Good advice also points to the next step. A toy that offers just enough challenge stays engaging for longer and increases the value of the purchase.