Microsoft has updated its guidance for over 500 million Windows 11 users, encouraging them to evaluate their security measures. The company asserts that Microsoft Defender, its built-in antivirus software, is adequate for most users, providing protection against potential risks from the moment the PC is powered on. While Microsoft acknowledges that its default protections are usually sufficient, it also notes that the decision to use third-party antivirus solutions depends on individual usage patterns and desired features. Users managing multiple devices, sharing devices with family, or seeking additional services like identity monitoring may consider third-party options. However, Microsoft warns that adding extra security tools can complicate system performance and incur unnecessary costs. The perception of built-in protection has evolved since the Windows XP and Windows 7 eras, with Windows 10 and 11 reinforcing the reliability of Microsoft Defender. Despite this, the guidance is not expected to significantly impact the third-party antivirus market, as testing has shown a variety of excellent options available for users looking to enhance their security.