I do not know much about batteries.
My son's Pilot battery kept dying - his wife was doing a lot of short trips. He installed a new battery and, as far as I understand, without changing his lifestyle, the battery does not fail anymore.
How about batteries that sit on the shelves for months and are still good when you put them in the vehicle?
Try to go to Autozone and ask if they can perform a load test on your battery. I would not just trust the dealer. I think I have seen a load tester at Harbor Freight for about thirty dollars. You can buy it and test the battery yourself.
Good luck,
Sam