Do I need advanced dining reservations?
The short answer is no. However, with the popularity of the Disney Dining Plans, more and more people are eating at the Disney restaurants and you almost must have an advanced dining reservation to get the time and restaurant you want, each day. Otherwise, be prepared to wait -- up to several hours or lose out on that restaurant, entirely.
Many people feel "tied down" by advanced dining reservations.
"I don't want to have to be somewhere."
"If I'm in EPCOT, I don't want to run all the way to Magic Kingdom for a dining appointment."
Great! Don't run to the Magic Kingdom or interrupt your vacation! You can cancel an advanced dining reservation, anytime. You can't get one at any time, however. Make sure you have something locked in.
If you're in EPCOT and want to take an available slot at San Angel instead of that ADR (Advanced Dining Reservation) you have at Crystal Palace, then do it!
The key is getting something on your schedule, so you don't miss out, altogether.