I can only share my limited experience... we went last year for our very first WDW vacation Me, DH, DS16, DD8 and DD5. We stayed 12 days and it was wonderful... we did not have to worry about cramming everything into one day. While we did MANY things,,, we realized that there are MANY things we did not even get to do. We are taking our second WDW vacation this year... for 1 week (end of Aug/Sept) We decided that we are not even doing the water parks,,, just the four theme parks trying to catch things we missed the first time. We LOVED the park hoppers.. the flexibility was more than worth it for us... We went to one park that morning and it was horribly crowded, so we hopped over to another and it was perfect. We did that over our whole trip... if we missed something at one park that we really wanted we could start at one park and finish up at another.