During the cold winter months, batteries are most prone to failure. If by chance you try to start your car and you hear several clicking sounds in succession, most likely your battery voltage is low or you have a terminal that is corroded. If you hear just one click and nothing more, it's possible your starter has failed.

A good practice for vehicles that aren't driven that often during winter months is to start them and run them 1-2 times a week to keep a charge in the battery or use a trickle charger / battery buddy to keep the battery life up.