Many people have a 2-to-1 rule about the parks: Allow twice as much time at DL as you'd spend at CA.
As far as total number of days, I think it depends on who is going (what ages and interests), how in-depth you want to see everything, and what kind of pace you'll take.
We were going on our first trip last fall, so everything was going to be new to us! Also, we were travelling with two small children, so not going to have a blistering pace. DH, DS6 and I figured out our must-do items for the trip, several that we'd like to see, and the rest was the icing on the cake.
We had a little over 7 days in the parks. I did not really schedule or plan days/times (other than things that were only offered on the weekend or a certain night, of course), and looking back I wish I had. We did a lot of unnecessary wandering around, just checking things out and getting the lay of the land. The first several days especially were less productive than the latter part of our trip.
And you'd think in 7 days we'd see it all, but we didn't. I don't think you
can see it all in one trip! But we did almost all of our must-dos (some things were closed for the season or for refurb or we didn't realize they were only on the weekend.) We repeated our favorite rides often! And had such a fabulous time that we can't wait to go back. There's still plenty more for us to see for the first time on our
next trip.
