Personally, not often, but I've been.
Some statistics here: https://www.tourismnewzealand.com/assets/insights/market-overview/TNZ-Insights-Infographic-Market-Snapshots-2024-AUS.pdf
Australia is New Zealand’s largest visitor market. Last year, 1.3 million Australians (44% of all arrivals) visited New Zealand, with 517,000 (40%) being holiday visitors.
I was there for four months in '88. No real plans to come back. Nothing against the place, I'm not much for travel anyway.
I've been 7 times in the last 25 years.
I've been twice, intending to go again at some point. The kids are keen on Japan being the next holiday destination. Maybe the one after that?
I've been twice, one trip right up and back down the North Island plus 3 hours on the South Island. Second trip was strictly Auckland. Would love to see more and explore the South Island more.
I grew up in New Zealand (aged 9 to 22) so technically been there heaps of times.
I've only been back once for a holiday since I moved back to Australia, and that was before covid happened.