H-1B extensions beyond 6 years are possible through an approved I-140 or a PERM labor certification pending for 1 year. For PERM-based extensions, you can apply before the 1-year mark, but the extension only becomes effective after a full year. For example, if your PERM was filed on November 1, 2023, and your current H-1B expires in October 2024, you could apply for an extension in July 2024. However, the extension would only be effective from November 1, 2024. You may need to leave the country temporarily if there's a gap between your current H-1B expiration and the extension's effective date.