I think it just depends on their personality, for instance i took ds1 to hi-5 when he was about 18 months i think. He sat still on my lap the whole time, but he was just that kind of baby, a non-mover. He's like that still as a 3 year old, very pensive and and predictable. DS2 is a totally different baby/toddler. I have had to insanely child proof my house in ways i never had to with ds1. Its weird!