Do I Need A Rental Car For Walt Disney World?
In my opinion, having a car at Disney World is a liability. If you are not arriving by car, then my advice is to avoid renting a car if possible and try to use the Disney transportation as much as possible, especially if you are staying on-property at one of the Disney Resort hotels.
If you are staying off-property at a non-Disney hotel, some nearby hotels will provide a shuttle service to the Disney parks. The advantage is that you will save on parking fees plus you will get dropped off close to the park entrance saving you a long walk or tram ride from the parking lot to the gate. The disadvantage is that you might have to wait for the shuttle to arrive as they may only run every so often and depending on how crowded the parks are, the shuttles might fill up quickly.
If your hotel does not offer this convenient service, or if the shuttles run too infrequently or are too crowded, then it might be worth it to use a ride sharing service such as Uber or Lyft, rather than renting a car. The round-trip cost of a quick ride to or from your hotel to the Disney parks might not be much more than what you would end up paying to park your car for the day at the Disney theme parks, but it is definitely more convenient as the ride-sharing services can usually drop you close to the front entrance of the theme park. The exception to this is the Magic Kingdom, where the ride sharing services must drop you at the transportation center across the lake and then you must take a boat or monorail over to the Magic Kingdom.