Mine was 3 when he became interested in ipad (1). I just bought it then so I was petrified he'd break it but nothing happened yet (ok if I just jinxed it I will buy ipad3
) He is now 5 and regularly asks for it (games, magnetic letters, interactive books, youtube for dinosaurs) Screen gets smudgy but not bad. And first, I do not allow him to use it for hours, second he gives it up after a little while. And I monitor what exactly he is doing (youtube is especially tricky, so I monitor it closely) It will be a loooong time before he gets his own tablet though. He asked me what I was reading on my ereaders and played with buttons but you know, old folks books have no pictures and it was boring.