The most common way of damaging tires is improper inflation. As tires lose pressure over time it causes them to experience irregular treadwear, poor vehicle handling and traction, and decreased gas mileage. Under inflated tires can build up excessive heat and blow out without warning. Pressure should be checked at least once a month using a good quality tire pressure gauge. Pressure should be checked when the tires are cold (tires have not been driven for 2 hours). You can find out what the proper inflation numbers on your tires are by checking the owner's manual of your vehicle. Even if the tires have been changed since the vehicle was new, the car manufacturers recommended pressures still apply. Also remember to check your spare tire for loss of air.