In today's saturated e-commerce market, it's critical that retailers closely track consumer demand to compete with Amazon. According to Women's Wear Daily, even Nordstrom  (JWN - Get Report) -- widely recognized for its customer service and free shipping -- is feeling Amazon's (AMZN - Get Report) impact.

Given a recent Onestop Internet survey, retailers might want to reconsider their return policies to drive more digital sales. The survey found that 70% of respondents said free returns would make them more likely to buy online. That underscores the importance of a more flexible consumer experience: Retailers need to give customers the ability to return merchandise that doesn't fit, or that they don't like.

Nearly 40% said finding the perfect fit while ordering apparel online is a challenge either every time or more than half the time. Furthermore, 65% of respondents said they would be willing to accept a shorter return period if it meant they could order multiple sizes online and only be charged for one unit, so long as they return the excess inventory within the allotted time frame.

Onestop Internet is a provider of e-commerce solutions, including digital design and video, call center, warehouse and fulfillment services. The company's clients include a number of major apparel brands.

It's not surprising that consumers seem to love Warby Parker's model, which allows them to try on five pairs of glasses at home over the span of five days. Shoppers can then decide which, if any, of the pairs they want to keep, and return the others for free.

The home try-on model perfectly combines consumers' desire for free returns and the ability to order multiple sizes/styles while only being charged for one item. The option to try on multiple styles at home is particularly appealing when buying eyewear. It's difficult for someone to gauge the right frame strictly via online images.

To be sure, such convenience may not be a major factor in whether a shopper converts to a brand, but it would certainly benefit those companies selling items that depend on perfect fit. For example, when it comes to shopping for a swimsuit, most people would agree that finding the right fit is critical, and that fit depends on each shopper's unique shape.

As such, it makes sense that new swimwear lines like Cocodune are introducing home try-on models. Cocodune allows shoppers to try on four items over the course of five days, and only charges for the items that a shopper keeps. This policy makes it more appealing for consumers to take a chance on the brand because they know they won't have to pay shipping for an item that doesn't look for fit right.

Another vertical within the fashion industry that could benefit from a policy like this is premium denim. Among the biggest challenges for denim companies to acquire new customers is getting them to look past the price and try on the first pair of jeans. Once they see and feel the difference in fit and quality that premium brands offer, they're more likely to convert.

Shoppers also tend to buy their first pair of jeans in-store at a Nordstrom or a Bloomingdales before making a second purchase directly from the brand's digital channel. A return policy that gives shoppers the option to try on multiple styles at home would likely encourage consumers to make that first purchase directly from the brand, which could significantly increase digital sales long-term.

There's no denying the Amazon is now dictating many retail trends. Other retailers, those with bricks-and-mortar operations and purely online companies, will have to adjust to keep up with changing consumer expectations. Free shipping was once a key factor in driving online sales. Now consumers want better return policies.

Companies who don't heed that trend may struggle to remain competitive.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.