GigaPoints earned are valid for 1 year upon crediting. But, as long as you keep on earning GigaPoints, your accumulated GigaPoints will follow the validity of the latest GigaPoints earned.
Example: Your 100 GigaPoints earned last November 26, 2020 will only expire on November 27, 2021 if no add load or Giga promo subscription were done from November 27, 2020 until November 26, 2021.