Auto Talk 101: Signs Car Battery Needs Replacement - as part of the expert series by GeoBeats. Age is the biggest one. If your battery is more than four or five years old, it is time to at least consider replacing it. You do not have to wait till you are stranded and you go up there and your car will not start. Another thing that people do not realize is that really hot weather is just as hard on a battery as really cold weather. People are used to the winter being a time when batteries fail, but batteries fail a lot when we get into that first high heat, upper 80's, 90's of summer. I sell a lot of batteries in late June and early July because of that. So if you know the age of your battery, you do not have to wait till you are stranded. If you open your hood and there is a lot of corrosion on your battery terminals, that is another possible indicator that the battery is getting old. There are other things that can cause that as well, but that is a good thing. Batteries normally have a date on them somewhere. Sometimes that is easier to see than others, but if you can see the date or the date has been stamped out on the top you can tell how old it is. If you get to the point your car is not starting, it is cranking really slowly, things like that, then you know it is urgent. But a lot of times you can catch it, you know, a few weeks before you get stranded and save yourself that hassle.