Battery life refers to the duration a device can operate before needing a recharge. It is typically measured in hours and depends on factors like the battery's capacity, the device's power consumption, and usage patterns. Devices such as smartphones, laptops, and tablets all have varying battery lives based on their design and intended use. To extend battery life, users can adjust settings like screen brightness, close unused applications, and enable power-saving modes. Regularly updating software can also help optimize performance. Understanding battery life is essential for managing device usage effectively and ensuring that devices like smartphones and laptops meet daily needs.