"I've been trying really hard to stick with it," she told the Herald nearly two months after she began the challenge.
"Most of the time it's all good and I have a pretty extensive second-hand wardrobe so it's sweet.
"For the first month of my challenge I didn't even go opshopping. I relied on things I already had and things people had passed down to me during that time."
A busy summer social calendar had tested her creativity, she said.
"I have had a couple of birthday drinks that were nice and classy, and I went to the orchestra and things like that. If people say 'dress fancy' I will usually be the most casual person there.
"Most of the time, I don't really plan [my outfits] in advance. If you have a specific event that you don't have something for I usually would go out and look for it in the opshops ... it is just more hit and miss if you find something that is actually right.
"If you're looking second-hand it could be anywhere."
She even snared a brand new bikini, still in its packaging, in time to hit beaches in Tauranga and the Coromandel over the holiday period.
"I am going to lots of beachy places so I will be taking lots of shorts and T-shirts and keeping it pretty casual. I might recycle some of the dresses I have already worn and take a nice party dress on holiday with me."
Inspired by Hong Kong eco-fashion organisation Redress' 365 Challenge, Holly hopes to highlight the environmental effects the industry's fast-changing trends create through textile waste, pollution, water and energy consumption.
"I have saved money by doing this because I really have bought about four items of clothing in the last month and they have been about $6 each.
