On past trips, we've usually had a car with us. Typically, we park it at the resort & hop the bus to the parks. It's nice to have available if we need to run to Walmart or want to pop out for a nice bite to eat, especially when staying at a resort without a great on-site dining option.
That said, on our last trip, we had a 8am PPO ressie at Crystal Palace. I figured driving from POFQ would be a better idea than taking a bus since I wasn't too sure I could rely on the bus to get me to MK in time. It was a rainy morning and fairly dark (as the clocks had just jumped ahead), and this was my first time actually driving to the TTC - all previous trips had been via bus. I incorrectly assumed the car in front of me was another park guest and just followed where they were going to park, since (did I mention it was dark and rainy?) I couldn't really see that far in front of me. I'm not really sure what parking lot I ended up in eventually, but I'm pretty sure it wasn't the one I was supposed to park in. Frightened my car would be towed if I tried to park, there, I then had to attempt to return to the proper lot, which involved another loop around the World. Needless to say, we were a little late to our reservation.