Oil is an important part of keeping an automobile running smoothly. There are many types of oil available for automobiles, each with their own benefits and drawbacks. The most common types of oil used in automobiles are conventional, synthetic, and high mileage. Conventional oil is the least expensive, but needs to be changed more often than the others. Synthetic oil is more expensive but provides the highest levels of protection and performance. High mileage oil is designed for older vehicles and helps to keep seals from drying out and reduce oil consumption. Ultimately, the type of oil you choose will depend on your budget, the age of your vehicle, and the level of performance you require for your vehicle.