How do I check if my Audi A2's battery needs to be replaced?

I recently purchased a used Audi A2 and I'm not sure if the battery needs to be replaced. The car seems to be starting fine, but I want to make sure I don't get stranded with a dead battery. What are the signs that indicate a battery replacement is necessary?

The easiest way to check if your battery needs to be replaced is by using a voltmeter. Connect the positive end of the voltmeter to the positive terminal of the battery and the negative end to the negative terminal. If the reading shows less than 12.4 volts, it's time to replace your battery.

If you notice your headlights or interior lights are dimmer than usual, it could be a sign of a failing battery. The lights draw power directly from the battery, so any decrease in brightness can indicate a problem.