Monitoring the battery voltage and the battery booster output voltage is crucial for maintaining the health and performance of the battery. By regularly checking the battery voltage, you can ensure that it is within the optimal range for proper functioning. Additionally, monitoring the battery booster output voltage allows you to verify that it is providing the necessary power to start the vehicle or operate other electrical components. By keeping a close eye on these voltages, you can detect any potential issues early on and take appropriate measures to prevent battery failure or electrical system malfunctions.