Calling to confirm is a must, in my humble opinion. For our trip last August, we made all of our ADR's yet when I called back to confirm them, I was told we had no ADR's! Luckily, since I called to confirm not too long after they were made, I was able to make all new ADR's where we wanted, just some of the times were a bit later than we had wanted. I actually called SEVERAL times to confirm after that-and will do the same on our next trip!