We just got back from DW with our DS age 7 soon to be 8, with autism. We rented strollers at all of the parks. Our son is quite big - 85 lbs so he was better in a double - in fact it was quite comfortable. If your child is much smaller, a single would be fine. The only problem is at MGM where the strollers are these very narrow canvas jogging strollers and the doubles have a divider in the middle. Anyway, keep in mind that you only have to pay once a day (a receipt from one can be used to pick one up at any other park that day). And think of it as a rental car -you don't have anything to show for that cost either at the end of the trip. The only difference would be if you think you might need one around your hotel, walking from the monorail/bus/boat to the park entrance, or at the airport. If you do, well worth it to bring your own so you will always have it - just make sure to check the weight since you'll be lugging it on buses, etc. Good luck!