We rarely take breaks and we have small children! Usually the youngest naps in the stroller, though, so we don't have to worry about toddler burnout. For the 2 older ones, we just play it by ear. Sometimes we will go back to the resort around 4 or so to shower and change for dinner, but often we will keep right on going especially if we are at EPCOT or MGM and plan to have dinner in the park. I'm always surprised by how much stamina my kids have...DH gets exhausted before they do. I think it's just all the excitement and adrenalin that keeps them going strong. However, once we get back to the room they crash.