Aday’s 5,000-person waitlist of “wear-testers” is fueling the direct-to-consumer apparel company’s approach to customer acquisition, data and product innovation.

In 2016, the brand ran a sponsored Facebook post directing people to sign up to become a wear-tester, which co-founder Nina Faulhaber considers the brand’s modernized version of the focus group. The promotion resulted in the waitlist, as well as the infrastructure for a customer-driven feedback loop. The wear-tester group of about 20 customers assigned to it, ranging in ages, lifestyles, careers and locations, and they’re regularly tapped for feedback in the form of online surveys, “missions” to complete while wearing the Aday piece, and try-on meetings over rosé at Aday’s New York offices.

“Our brand philosophy is about creating clothing that will last a long time, with a timelessness and versatility to it. That means we have to do a lot more on the testing side of things,” said Faulhaber. “Traditional fashion brands are focused more on designing for a specific season’s trends, and churning out new designs, which means it doesn’t matter as much how well a product holds up. For us, that’s what matters the most.”

New products are subjected to the tester program before launch, including an “intensive” four week digital survey process, and then once they’ve hit the market, customers are regularly recruited to give feedback on how something holds up over time, as they’re worn for different activities. The Aday design and customer-service teams work together to maintain a mass Excel spreadsheet that houses all feedback an item has received, whether it’s through an online comment, an interaction with someone on the team, the reasoning for a return, or the wear-tester program. From there, the teams identify recurring themes and feed that information back into the product-development process, where changes can be made.

As a result of this feedback system, Aday has re-released its “Throw and Roll” leggings after hearing from customers that the waistband slipped down over the course of the day. Its “Something Borrowed” button-down shirt was remade with a sturdier fabric that’s more wrinkle-resistant than the first version. Beyond product innovation, the brand has found that wear-tester program participants are more loyal customers. The brand’s product survey emails have a higher open rate than any other email it sends.

Aday’s long-term goal is to scale the program. To do that, the brand plans to add more participants and create a more robust digital survey with more open-ended questions. It also wants to add more in-person events outside of New York, which Faulhaber said result in the most insightful feedback.

“For us, it fits into our strategy of high requirements for our pieces. We want them to be long-lasting, sustainable, machine washable, so we need that feedback loop and the ability to react and be proactive,” said Faulhaber. “This is the benefit of being direct only — there are no wholesale retailers, where feedback gets lost.”

While direct customer relationships still influence modern retail strategies for both new and traditional brands, digitally native consumer startups have had to think outside the box — and outside of VC funding — to find new ways to grow. Paid customer acquisition on social has gotten prohibitively more expensive, with less impactful results.

“Young brands need to be investing in customer loyalty, not just scale, scale, scale,” said Scott Tannen, principal at investment firm Red5 Capital and founder of Boll & Branch. “Having a strong return rate signals that this is a company who knows product builds a brand, not a ton of VC money or ad spend.”

Aday, which has raised $2 million in venture funding, has looked to its wear-tester program, as well as its list of applicants, who give information like their age, location, and sizing to the brand, in order to cull first-party data. It also launched an ambassador program in March of this year to reward 50 of its most active customers with referral codes and rewards for recruiting new customers.

“These [ambassadors] buy more often, engage more often, and visit more often,” said Faulhaber. The brand has hired a full-time employee to lead the ambassador program as well as the wear-tester program, with the goal of combining the two into a customer data and research program that can scale beyond an Excel spreadsheet. The group of ambassadors and product testers will contribute to how the brand acquires new customers and iterates on product design.

“We design clothing to solve problems for people, and if we have something with a high return-rate, that’s not going to cut it,” said Faulhaber.