the battery in my vehicle was manufactured in the 41st week of 2017. I've never had any issues with it. In my online research, many sources say batteries last from 3-5 years, which would make my battery archaic. When I tested it with a multimeter, it read 12.4V with the engine off. I've never had any issues starting the car.
What explains how this battery is still alive despite it's age? Is the 3-5 year age expectancy accurate? Should I replace it? Given how old it is, I have it in my mind that the battery could die suddenly, any day now. What should I do to stay ahead of it's inevitable death?