Tires are a key part of every vehicle yet they can be one of the most overlooked parts when car owners are maintaining their cars.When the overall safety of a vehicle depends heavily on the type of tires being used, it is important to ensure that the right tires are used. In order to buy new tires to suit a vehicle, some key aspects cannot be overlooked. Since tires don't last forever it is important to upgrade them periodically to make sure there isn't a loss in traction. In order to know when old tires need to be upgraded, car owners must first examine the older tires for wear and tear. This can be done visually or using the penny test. Some tire brands have a wear/tear bar on their tires. Once the tread has been worn down to that bar, it is time to replace the tires. Car owners can also have their local mechanic look at the tires to decide whether or not they need to be replaced.Purchasing the right tire for a vehicle is also important. Drivers who are unsure of what tire brand and size will suit their vehicle best should visit their local mechanic or car dealership. Either one of these should be able to point them in the right direction.In an effort to save money, some car owners opt to buy used tires. While this is a cost effective move, it isn't always the safest route. When people purchase used tires, they usually check the exterior to assess wear and damage. However, not all tire damage is visible on the outside. Several factors can play into the overall safety of used tires yet those factors are hard to judge just by sight alone. Used tire buyers do not know if a tire was driven under inflated, driven at excessively high speeds or driven overloaded. Either of these factors can take away from the reliability of a tire and are hard to assess with the naked eye. It is always better to err on the side of caution and purchase new tires from a reputable store.With tires being such an important aspect of vehicle safety, drivers cannot afford to be anything but diligent when making purchase decisions.