How to troubleshoot a faulty starter motor on an Audi A5?

I've been having trouble starting my Audi A5 lately, and I suspect the starter motor might be the issue. What are some steps I can take to diagnose and fix this problem?

First, check the battery and connections for any signs of wear or corrosion. Next, test the starter motor by using a multimeter to measure the voltage at the starter terminals while attempting to start the car. If the voltage is low, it could indicate a faulty starter motor. Other potential causes could be a damaged starter relay or ignition switch.