Most new batteries last around 5 years. Factors including climate, over and under charging can impact on the life of a battery. In most cases, if a battery is over four or five years old, it should be replaced.
Auto mechanics and service facilities will install batteries, but it can also be done by you quickly and it would be less expensive.

The procedure for replacing a battery is very simple if certain details and safety rules are followed:

• Disconnect the negative battery cable, then disconnect the positive cable.
  
• Remove the metal clamp that holds the battery in the battery tray.
  
• If rust is found in the bottom of the tray, wash with plain water and let the tray dry before installing the battery.
  
• After drying, put the new battery into the tray and attach the metal clamps to secure the battery. These metal clamps should also be checked for rust or corrosion.
  
• Before re-attaching the battery cables, make sure that the insides of the cable connectors are free from rust or corrosion. If there is rust or corrosion present, use a thick paste of household baking soda and water to scrub the insides of the cable ends.
  
• This same paste can be used to clean the metal battery clamp. A piece of wire brush for scrubbing off this corrosion may be obtained from an auto parts store.
  
• Spay the metal clamp with WD-40.
  
• Spray cable ends once every six months to guard against corrosion.
  
• Make sure cable wires are not frayed to insure a safe connection.
  
• Re-attach positive and then negative cables to the posts and then tighten until it is firm, but not too tight.
  

If for some reason the vehicle does not start, seek the assistance of a mechanic because there might be another problem.