We stay longer and try to take a break mid-day every day. Sometimes, though, we need a sleep-in day. DH is content on those days to wait until later to go to the parks, if at all. I usually like to go a little earlier.
Our kids have made us (me) change our habits...they LOVE the pools, and would rather swim than stand in line. They know we will be back, and we rarely wait in more than a 20min line for anything. It's FastPass, EMH, or try again next time. We will go early to the parks to get our chances to ride the faves (Soarin', Everest, etc) without a wait, but then we leave and go swim or go to DTD, or just nap in the villa! We love the late EMH hours, but need a rest or nap in the afternoon if we don't want to wear out early.
DVC has helped us (esp. me) take it easy, enjoy the vacation and not measure the trip in how many rides we rode or how many hours we spent in the park.
We do the same thing as pp, make a list of each family member's "non-negotiables" - can be different each trip. When the focus is on those activities, we end up making some great memories. One year my DD wanted to spend some time at Rafiki's Planet Watch, so we spent a while out there checking everything out. Last summer, the youngest DD wanted to ride the park balloon at DTD. They loved getting to pick something special to do, and our focus has shifted from checking everything off a list to really enjoying and appreciating it all.
Another fave of our kids....night swims. The pools are generally empty at night, and the lifeguards leave at 10, but the pools are still open (slides closed) and we have had lots of fun just playing with our kids, relaxing in the water (or jacuzzi) at the end of the day - and then we all sleep good!
Good luck...it has taken me longer than the rest of my family to change my style, but I am glad I have. We enjoy each other with so much less stress and exhaustion, and enjoy Disney more too!