I can’t dispute the advice of others to change 12v batteries after 2-3 years, but that has not been a need for me at all. Still on original 12v in my 2012 SL. Car has not been garaged for the last 14 months so the solar panel on its hatch may be trickle-charging it. When I do park it in the garage to charge overnight, I connect the 12v to a batter tender as well, and I keep the fluid topped. Seems to be working well. That said, I’ve only had one vehicle 12v battery die quickly (less than 6 months) and it was in a new vehicle and replaced under warranty. My newest vehicle is my 23rd, and all had their original 12v batteries when traded usually between their 4th and 9th year of life with me. One exception, my 1964 Ford Thunderbird. It gets driven very little but over the decades I’ve replaced the 12v a few times even though I always keep it on a battery tender. I’ve owned most of these cars living in Florida, the Midwest, and now North Carolina. Either I’ve been unusually lucky, or the 12v batteries in the cars I’ve purchased were a cut above in longevity for whatever reason.
Nissan 2012 LEAF SL, 13,500 miles, 9 bars, 35-mile range
Tesla Model 3: Long Range Rear Wheel Drive | Extended AutoPilot | Full Self-Driving | HW3 Upgrade
Delivered: July, 2018 | 14,400 miles | PM me for Tesla referral code