Returning the rental car late or exceeding the agreed-upon mileage limit may result in additional charges. Most rental car companies have specific policies and fees for late returns and mileage overages. It’s important to review the rental agreement and understand the terms and conditions related to returns and mileage limits. If you anticipate any changes to your rental duration or mileage, it’s advisable to contact the rental car company in advance to discuss possible alternatives or adjustments.