Add it once and it stays up to date. New, changed, and removed events update on their own.
Apple CalendariPhone, iPad, and Mac. Usually updates within a few hours. Google CalendarCopies the link and opens Google Calendar. Paste it and click "Add calendar." Can take up to a day to update.Google Calendar can only add calendars from a web browser, not from the phone app. On a phone, if the page does not open, use a computer or your browser's "Desktop site" option.