I got 6-7 years out of the OEM battery in my Ford E-350 (RV chassis). I’d disconnect the ground cable in the late fall and hook it back up in the spring, and the engine would fire on the first crank. But then one spring, nothing happened. As it turns out, the battery had frozen during a sustained freezing spell. Otherwise, it would probably still be working.
I replaced it with an Interstate, which is still cranking well, and I bought an electric battery blanket for freezing weather.
I put a new Optima battery in my 89 Ford work truck about 12 years ago. The truck is driven maybe 10 to 15 times a year. Still starts right up, even after sitting for months.
Optima batteries are a type of AGM, absorbed glass mat battery in a spiral shape. Different from an acid bath standard type.
I have had an Optima Red Top in my car for 15 years. I will be going to a Yellow Top sometime this year. The yellow top is a more deep cycle battery that is more suited to the additional electronics I have added to the car, dash cameras, sound system, etc.
See the post from jz78817 above.
Modern fuel injection has made cars far easier starting than they were in the days of carburetors. Sure, a carb in good tune with the choke working right, and a driver that knows how many priming pumps of the accelerator are needed based on outside air temperature and how warm the engine might be they COULD start right up, but it was not uncommon to hear my mom or a neighbor grinding for 5-10 minutes as they repeatably flooded the engine by lifting their foot every time they let off the starter.
Besides easier starting, modern alternators have a voltage regulator that compensates the charging voltage for temperature (about -26mV / deg.C) which helps avoid under charging and overcharging.
Generally speaking your regular lead-acid batteries don’t usually last all that long in hot weather places- 3-5 years is about all you can reasonably expect. AGM and gel type batteries last longer, but as far as I can tell, aren’t really cost effective vs. a regular lead-acid battery with a decent warranty that pro-rates based on the warranty duration.
They also use thinner plates than they used to.
For the same amount of lead, you can make the plates thin or you can make them thick. If you make them thin, you’ll end up with more surface area, which means more power (i.e. cold cranking amps), but they don’t have as much reserve inside the plates. If you make the plates thick, you end up with less power (fewer cold cranking amps) but the battery has more of a reserve. The main difference between a regular battery and a deep cycle battery is that deep cycle batteries have thicker plates.
The way a lead acid battery works is you have two plates, one made of lead and the other made of lead oxide. In between these plates, you have a mix of sulfuric acid and water for the electrolyte. As the battery discharges, both plates turn into lead sulfate, and the sulfuric acid turns into water. As you charge the battery, the plates turn back into lead and lead oxide, and the water turns back into sulfuric acid.
Generally, this process is reversible, but if you discharge the battery too far, hard crystals of lead sulfate will form that won’t break up and turn back into lead and lead oxide during the charging process, which results in a permanent loss of capacity for the battery (technically there are ways of breaking up these crystals, but a normal battery charger or a car’s charging system isn’t capable of it).
Heat kills all batteries, and lead acid batteries are no exception. The heat speeds up the chemical reactions inside the battery, and once again you end up with lead sulfate crystals on the plates that won’t break up, along with the corresponding loss of capacity.
Your battery can generally lose a lot of capacity and still have your engine start, so you may not notice the loss of capacity at all until it gets cold when it’s harder to start the car, and then you may end up completely killing what’s left of the battery just because it is so worn out.
Again, as I said upthread, one way to significantly increase the lifespan of your battery is to buy an oversized battery. It won’t discharge as much (percentage of its total capacity) so you’ll end up with less sulfate problems on the plates, so the wear and tear on the battery from normal use will be significantly lessened. And because it does have more capacity, even if it loses some capacity, it will still have plenty of capacity left with which to start your engine.
10 to 15 year (or more) lifespans are easily possible, although excessive heat can still shorten that significantly.
FTR, I haven’t ever heard of a 10 year battery life here in Texas; my wife’s VW Passat factory battery lasted six, and that was reckoned unusual.
Then again, we have high ambiet temps upwards of 100F/38C regularly in the summer with low temps around 80F/26C, and I’m sure it can be even hotter in the engine compartment under certain conditions.
Thanks for reminding me - our newer car just passed its second birthday, need to get the battery checked.
I hear AGM batteries mentioned - do they fare any better in the hot Arizona climate than lead acids?
thanks for the thorough breakdown of how batteries work. I didn’t realize the acid turned to water when it was discharged. The battery hydrometer makes more sense now.
However, I’ve never had a modern battery last 10 years. And the sneaky bastards have never given me warning they were about to fail. Based on what you said it’s because the newer ones have so much more cold cranking amps that you never notice the loss until it takes a complete dump.
I suppose I could just measure the voltage drop. You’d think one of the computers would do that for you. I recently bought a USB plug in charger with voltage display. I wish it was built in.
My reply can’t be statistically significant as my sample is one. 
However, this is my first AGM battery (in the truck) and I did get 4 years out of it. And my truck has the auto stop-start feature so it gets a lot more exercise than the battery in the car (not AGM, got just over 2 years).