A car trade-in is a process where a vehicle owner exchanges their current car at a dealership as part of the payment for a new or used vehicle. The dealership assesses the value of the trade-in based on its condition, age, mileage, and market demand. This value is then deducted from the price of the new vehicle, making it a convenient option for buyers. Trade-ins can simplify the car buying process by reducing the amount of cash needed upfront. Additionally, they can save time, as the dealership handles the sale of the old vehicle. Overall, a car trade-in can be a practical choice for many car buyers.