Whether or not you need two cars depends on your lifestyles in retirement. If your interests and hobbies are different and you are frequently away from home at the same time going in different directions, then you might need two cars.
If most of your activities away from home are done together, then you may only need one car. This may be especially true if you are able to walk or ride a bicycle to run errands near the house.
For people that are moving and want to get an idea how walkable their new neighborhood is, this is a pretty good website:
https://www.walkscore.com/
My wife and I have two cars, but once she retired a few years ago we could easily get by with one car. I still work part time, but work from home, so I don't normally need a car.
I kept a spreadsheet for over a year and tracked the number of times that both of our cars were away from home at the same time. For us, in most cases, one of us could easily have shifted the timing of our car usage to avoid the need for a second car. For example, if I am at a club meeting and my wife is at the grocery store, the grocery store trip could easily have been shifted to another day or time.
We found that on average, there was about one instance every couple of months where we needed two cars, since we were going in different directions at the same time, when neither event could be shifted to another time. In the long run, it would be much cheaper for one of us to take a taxi or use ridesharing (Uber or Lyft) once every couple of months than to maintain a second car.
Both cars are paid for so we have chosen to keep them for now. But when the first car reaches the end of its life, we will probably experiment with only having one car. This is not an irreversible decision, so we can always get a second car if we wish.