Signs you need to replace your car battery
Difficulty Starting Your Vehicle
Under usual circustances, the battery should immediately send the required charge to start the engine instantly. If that's not the case, there is an issue with the battery.
Cranking/Clicking noises when turning the ignition switch
This could be an issue with the starter or a failing battery.
Signs of corrosion
Corrosion can be easily cleaned up so you can have your battery working again but in most cases, it usually means it is time to replace your car battery.
End of lifetime
Most car batteries are expected to last between 3-5 years. Prolonging this will extend your chances of a sudden breakdown.