COBI sets are popular with anyone aged 6 - 106! From experience, children ages 6+ can build smaller sets by themselves. Some sets are suitable for 7+ and the pieces are quite fiddly which younger children may struggle with. However, this can be easily overcome with a little adult supervision. The individual pieces can also be a choking hazard for infants under 3. Although the sets are classified as toys with moving parts, they are also replica scale models made of plastic bricks so will not withstand too much rough play.