My 5 1/2 dd and I just did 10 days in December. I brought the stroller, first and foremost because we had an evening flight and I knew I'd never get through the airport with out it. (We were delayed an hour, and ended up checking in at 1am.) The first two days, she didn't use it and did fine. I missed it because I had to carry my backpack!! The rest of the trip she used it on and off.
However, a friend joined us with her early-morning kid (v. my night kid), so my dd didn't really get enough rest. Plus, we stayed at CD, specifically so we could walk back, so I knew I wanted the stroller for that.
FWIW, she hasn't used a stroller in forever. But I figured I needed it for the airports, I know I can't carry her for even short distances, so I figured I'd rather bring it and NOT use it than have to pay to rent.
Now, our next trip is after her 6th bd, but it looks like we'll be at the airport either in the late evening or early morning, so we'll probably drag it down again! Although i don't think she'd be as likely to use it.