Most batteries are replaced on the first cold morning that the car won't start. The average life of a battery is three and one-half years. If you are driving around with a battery that is older than that, then you shouldn't be surprised if you are stranded at the train station parking lot or the shopping center when it is 10 degrees below zero and the wind is blowing at 20 m.p.h. You are probably thinking to yourself that preventive maintenance is too expensive to follow. The fact is, preventive maintenance is cheaper in the long run than reactionary maintenance.
Most people budget only for car payments, insurance, and gas.
All that really needs to be done is to keep the close track of the miles you drive each week. Set aside ten cents for each mile that you drive and place this money in an interest bearing account. That will buy a lot of maintenance. Any money left over can either be left in the account to let your balance grow, or can be put towards the principal of your car loan. This will reduce both the interest you are paying as well as the number of payments.