OK, at the house we have 3, OK OK, now 2, stepson moved out, one of the Kicks(wife's, Executive model or about SR level in USA/Canada) had the battery replaced about 18 months ago, stepson's(Sense, 5MT) about the same time. These two are about a year older than mine(Sense 5MT), that will be 5 in August, I have NOT replaced the battery, have ran battery tests at the dealership and on a personal level with my Bosch and Schumacher battery testers and it still going strong, did replace the fob's battery out of a whim, was about 3yrs old and I simply don't trust those batteries.
I have a sound system and use the vehicle basically ONLY on weekend and don't drive more than 200 kms/week or during the weekend.
My dashcam I have it with a connector directly to the fuse box where is always "live". Mostly used when I am not parked at home, since I use a car cover, no need for the paint to get sunlight and rain for fun.
I did ask the dealership's shop for wife's battery back and had it tested, it still was at 90%, they just wanted to make a buck or 2.
How do I keep my batteries so long, is a question I get asked a lot; simple, I take a long drive, steady RPMs where I know the alternator is charging.
Wife's car had ABS/TC lights ON for a few days, DTCs showed 'Low Voltage' made a long trip, about 300kms total, issue was gone after first food stop at 50kms.
Manufacturers are installing the barest minimum in vehicles that need more. Probably, when I have to replace my OEM Varta, I will have to modify the engine bay to be able to install a larger AH capacity one.
Will keep you posted.