Needing additional liability coverage is a personal preference. As an at-fault accident can easily exceed your state’s minimum bodily injury and property damage limits, additional coverage ensures you won’t have to pay out of pocket for damages.
That said, if you have a car insurance policy, you would have additional coverage already. When reserving a trip, it never hurts to check the price of adding additional coverage. If it’s something you can afford, it never hurts to have extra protection.