Google Calendar has a limitation where repeating events will stop repeating after they have occurred 730 times. Once an event has reached the limit of 730 occurrences it will stop appearing on your calendar without any warning, which can cause significant problems.
For an event that occurs daily this limit will be reached in just 2 years, and for an event that occurs weekly the limit will be reached in 14 years. That might seem like a long time but many people (including myself) have been using digital calendars for 20+ years, and as we continue to use them our risk increases for hitting this limit and having our events disappear.