Your car is starting just fine and everything is working as it should, so why be concerned about your battery until it stops working for you?
Here is what you should know: batteries deteriorate over time from normal use, and the condition of a battery should be checked regularly as part of a complete automotive service. This is easily done by performing a load test on the battery using a special piece of equipment that is connected to the battery. This equipment applies an electrical load to the battery for 15 seconds at which time the voltage of the battery is measured. A healthy battery’s voltage needs to be at or above 9.7 volts. If the voltage measures below 9.7 volts, the battery is considered unreliable and may fail to start the vehicle at any time.
It is also important to know that a weak battery causes the vehicle charging system to work harder than designed and will result in the alternator failing sooner, which is a much more expensive repair than replacing the battery.
A competent repair/service facility performs the battery check for their customers and advises them to install a new battery before they become stranded somewhere. During the winter, for example, it is important to know that a healthy battery at 80 degrees outside temperature has only half of its output at 0 (zero) degrees, so it is important to check a battery before traveling in any cold climate.
As for the expense, batteries come in all shapes and sizes and quality levels. Generally, the lower the cost of the battery, the shorter the service life. It is important to purchase a battery that matches your vehicle’s manufacturer-recommended size and power. There is no “one size fits all”. What is inside the battery, called plates, dictates the quality; the size and number of plates in a battery determine how many amps it can deliver, as well as its service life, its warranty and its price.
Lastly, the battery needs to be installed correctly. The cables that connect the battery to the vehicle must be free of corrosion and connected properly. If the cables are connected to the battery in reverse order, the vehicle’s computers will be damaged.
So, yes, even if your vehicle still starts and runs, the battery could be on its last legs, and a good quality, long-lasting battery will cost more.