The battery is hard to reach because it sits beneath the center console, but a fast online search suggests that you should change it every four years. Despite what is on today's automobiles, replacing it will not be inexpensive. When it requires replacing or there's a problem, a red light near the button looks to light up. If you don't update the battery, Kia has a statement or disclaimer that covers themselves.
If the caution light is on, the mot might not pass.