What type of fabric is often used for its durability and is popular in casual clothing?

Denim is a type of fabric known for its exceptional durability and sturdiness, making it a staple in casual clothing. This heavy-duty cotton twill weave is particularly favored for items such as jeans, jackets, and skirts due to its ability to withstand wear and tear, as well as its resistance to fading and stretching. The rugged nature of denim allows it to maintain its shape and integrity over time, which is why it has become synonymous with casual, everyday wear.

While cashmere is a luxurious and soft fabric, it is not typically associated with durability, as it's more delicate and requires careful handling. Polyester is a synthetic fabric that can offer some durability but is often used in blends rather than as a standalone fabric for casual clothing. Spandex, known for its stretch and elasticity, is primarily used for athletic wear and fitted garments, rather than basic casual clothing. Thus, denim stands out as the most suitable choice for its combination of durability and popularity in casual attire.