We took our son at almost 3 and rented from Kingdom Strollers. The experience was amazing and the stroller was top notch. If I was going to cut somewhere on vacation, the stroller wouldn't be it. We didn't want to worry about ours getting damaged and didn't want to lug it around the airport. Our son did great walking on his own and carrying his own little roller bag in the airport but we got a lot more done in the parks with a stroller. It was also key for carrying all of our stuff with us. It was $60 for 4-7 nights and they gave us a Citi Mini which was amazing, so easy to collapse for the buses.
We live very close to a large theme park and still bring our stroller with us even though DS walks most of the time. There's so much ground to cover- we walked miles and miles in WDW, I would rather have the peace of mind knowing that we can throw DS in the stroller if we need to. Also our son is quite heavy at almost 40 lbs at 3.5. I can barely carry him halfway around our neighborhood if I needed to, which is only 0.2 miles!