Consumer Reports recommends testing your battery every year to find out if its running low, and replacing it before you get stranded. This will save you from a big headache, Consumer Reports says, and you can usually save money, too. Car batteries look very similar, so how can you tell which one will go the distance? Testers also simulate a vehicle starting thousands of times, just the way you rely on your car battery year after year. If youre replacing the battery yourself, Consumer Reports says dont let the old one sit around.