"I treat them as triplets. It's so much easier and less stress. We're a close family and we have a family party. The kids also go to their dad and have another party there."
Another tip is to keep it simple - instead of making three separate birthday cakes Ms Horne said she baked cupcakes.
"If you keep on having extravagant parties you have to keep on topping them up."
This year Ms Horne and the kids will be going on a trip to Kmart in Tauranga, "to buy toys...and clothes", according to Maia and Graegan.
In previous years they had gone on adventures to Rainbows End and Butterfly Creek in Auckland.
Aleyah, Graegan and Maia said people often didn't believe they shared the same birthday.
Aleyah, who attends Western Heights High School, said as she got older she would probably have her own birthday celebration.
Her mum said that was understandable.
"She wants to do her own things with own friends. There's two years difference between her and the twins so that make sense."
Graegan and Maia, who go to Kaitao Middle School, agreed one day they would want their own parties too.