The answer to that question is that it depends. There are several factors that will determine if the battery will last several years or only until the warranty expires. Naturally, human error plays a part in the story, but it isn’t the only thing.
Once upon a time, batteries could be serviced fairly easily. As I’m married to a mechanic, I’m tolerably familiar although I couldn’t give you details. It involves adding distilled water (I think) to any cells that are about to go dry.
Unfortunately, most modern batteries don’t have that as an option so the battery life is likely to be a good deal shorter. There are still things that can be done to prolong the battery’s life. One of them is to make sure it maintains a good charge level.
That is relatively easy if the vehicle is a daily driver that get a good charge on open roads such as the freeway. It is a good idea to keep an eye on the alternator to make sure it is providing enough of a charge while you are driving.
If the vehicle only gets driven once a week (or less) you may want to invest in a trickle charger. This device can keep the battery charged between outings so that it stays in good shape. If you aren’t sure how to use a trickle charger, make sure to ask your mechanic to show you the right (and wrong) way to use it.
Here is where human error can play a role in how long your car battery will last. First, anytime you let the battery discharge completely, you run the risk of having to replace it. This is especially true if it’s a cheaper battery. More expensive batteries may be able to handle this once, but it will damage the battery.
It is easy to forget that something is on in your car, especially now that we have headlights that stay on for a while after we turn the car off. There can also be a mechanical problem with the vehicle that will cause the battery to discharge. This is why the vehicle should be inspected regularly to make sure it is in good condition.
The next question is how do you know when your battery needs replaced? The obvious answer is when it no longer starts your vehicle, but as mentioned above that may not be the case. Even though my husband could make the call on his own, we use Triple A when our vehicles either need jumped or there is doubt about the battery. Read the article about how to jump a car battery
That does not mean we buy the battery from the Triple A vehicle. My husband is choosy about batteries and will usually have the vehicle towed home and then go to purchase a battery that fits our needs best. The company is reliable in testing, however. They provide hard copy to show the exact state of the battery.