Great question. It depends on the stipulations of your contract.
Some degree of tire wear will be expected under normal wear and tear. If your tires fall into that category, you won’t incur any additional costs.
However, if the tread is shallower—less than 1/8 of an inch on average—you’ll be on the hook for getting those replaced.
If you do have to replace the tires, make sure you replace them with the same size and specifications as the original. The information about your tires can be found on the tires or on a placard on the driver’s side door. Keep in mind, you’ll likely need to replace more than one tire for balance and alignment.