We have been when our daughter was 2.5, 3.5, 8 and are planning to go this year a week after her 12th birthday. I feel like our best trips were when she was 2.5 and 3.5 years old. It was magical for her, and she was still stroller age so when she got tired she could just crash for a bit. This next trip will be completely different from any of the previous, but I'm looking forward to Disney from a different perspective. We are doing the Day of Thrills tour and then a lot of whatever we feel like days.