[throwaway788]

Isn’t the point to avoid severe outbreaks in the first place, and thereby not needing extensive periods of restrictions.

I think the perfect time would be when effective oral anti-virals are readily available, they are just around the corner. The average daily cases are increasing and the 4th/5th wave (depending on location) is ramping up now - exactly the wrong time for a country like NZ to change international quarantine.