FROM MY PERSONAL EXPERIENCES
Those who visit the parks often know it and use it all the time, but if you go only once in a while you might even forget about it. No questions here, this app will be your best friend in the park.
If the wait time states 30min, is really about 10 min wait. 20 min is what, in most of the rides, will take you to get from the entrance to your seat ( might be a long way in)
Hot rides mostly those where kids are allowed will be packed in the morning check what is available with less wait time and come back to that hot ride later. Lines get much smaller by 6-7 pm
Check Menu and prices and then order your food through the app and pick up later. Trust me, the pickup line is much faster.
Ask if hotel provides a shuttle service If chosen to drive, same parking ticket is valid at all 4 parks on that day. Remember where you park. Park at Epcot and head to Magic Kingdom fireworks on Mono Rail. it will be faster to get out after the show.
A hat to protect you from the sun
Really comfortable shoes
A rain poncho, because umbrella will not do