For my little one, longer is better! We stayed 10 nights when he was 9 weeks old, 9 nights when he was 15 months old, 5 nights when he was 21 months old, and we have a 4 night trip planned around his 2nd birthday. In October, we will go back for 8/9 nights (Luke will be 27 months. For me, the shorter trips are too short. We do them anyway, because a little Disney is better than no Dosney! But even flying, it still feels rushed. We like to take it slower with a little one. We like to take breaks or leave early. We like to have sit down meals to rest and get out of the heat. We like to have at least a couple days per park so that we can FP different rides and hit everything without long waits. You can never see it all, but a long trip (8-10 nights), allows us to see most everything we want without a lot of rushing. And to me, that's the ideal scenario with a little one - enjoy attractions and dining with minimal waiting and minimal stress/rushing. Our fall 2015 trip is already booked, but I would really like to do 12 nights for our 2016 trip!