I love the idea of this clock and I think it would be most effective if used starting at around age 1 - 1 1/2. Our 3 year old like the clock and loves saying the time on the clock every 1 minute. As far as training has gone so far it just gives him a reason to yell, "it's green!" or "it's still red(?!)". To be fair, he's a rambunctious little guy so I already knew this would be a very time consuming process. Still I love the idea and I cannot wait to get him on track. [This review was collected as part of a promotion.]