Had to replace Volvo battery after 3 1/2 years. Was under warranty. Why did it not last longer. Our son replaced his volvo XC 60 about the same length of time . His is a 2015.
Batteries can fail at anytime. If you make short trips and the battery does not get fully charged that can shorten the life of the battery. A hot climate can shorten the life of a battery. I preemptively replace mine at 3-4 years. Others on this site will keep theirs until they fail.
We test our batteries each year and this year the battery in my 12 year old Toyota only drew 75% of its rated Cold Cranking Amps.
That would be OK in the summer, but on a cold morning it would not be enough. So we replaced it with a new heavy duty unit.
Waiting till your car won;t start is foolish.
We had a battery fail at just under 3 years.
It was bought brand new at Walmart. Luckily I keep the receipts, and they gave me a brand new one for no charge.
I had a top-of-the-line battery from Autozone that failed a load test a couple of weeks before the end of its 3 year warranty. Because Autozone keeps an electronic record of battery purchases, I didn’t even have to rely on my almost illegible receipt, and they cheerfully replaced the battery, gratis.
What part of the country do you live in? Southern states (heat) are killer on batteries. 4 years seems to be the norm in places like FL and TX.
On a 2016 & 2015 car that should be the OEM battery that would make it `year or two older depending when the car was built and how long it was before the car was sold.
New cars have systems that are always on, waiting to detect the remote fob as you get close to the car, for example. If the fob is left too close, or even in the car, the car will turn on the systems even more and wait for you to push the start button. That alone can kill a battery, so keep the fob far away from the car - at least 20 feet. It seems to be able to sense the fob through a normal interior wall, so pay attention. One day last week our 2016 CR-V was DEAD as can be, for no obvious reason, and I fully recharged the battery and got it going again. So far its been fine, so maybe somehow it was on all night? I’ll never know. Around here batteries last a long time because it’s never hot or cold much, averages around 55 - 60 all year in the garage where it stays. My Miata battery lasted 17 years, and I just changed a scooter battery that was new in 2008.