Customers are a lot more fabric conscious than they used to be. Fabric knowledge is improving and ensuring you select the right fabrics could majorly affect sales. Fast fashion brands often go for cheaper synthetic fabrics.
When people shop they consider how the product will wear over time, working with the appropriate fabric for the function of the garment is essential and will potentially increase customer satisfaction and repeat customers. If you are making a product that needs to be durable or has a specific function it may be important to run wearer trials in the final fabric to test its performance over time.
What to consider when choosing a fabric; is the fabric of the right weight and drape. This will create the shape of the garment, understanding the behaviour of fabrics in different patterns is important when designing.
Choosing a fabric that fits the lifestyle of your customer will impact the customer's decision to buy. How the garment has to be cared for is important. For example, if a fabric has to be dry cleaned or if it can be machine washed. Considering the use of the garment like if they are pyjamas the customer may not want to dry clean them but if it's outerwear they might not mind having to dry clean as it will be necessary less frequently.
Choosing a fabric that fits into the price range of your target audience, if you have created luxury branding you might want to work with a high-quality fabric. Every audience has a different price range and is happy to spend a different amount on a range of different fabrics.