The Martindale rub test measures how much surface friction a fabric can withstand before it shows visible wear. At 90,000 rubs, the Lush range sits significantly above what most residential curtain fabrics offer. In practical terms, this means years of daily drawing and closing — grabbing the fabric, pulling it across the rod, handling it while cleaning — without the pilling, thinning, or surface degradation that lower-rated fabrics develop over time. It's the kind of specification that rarely shows up on a product page but makes a real difference to how the curtain looks in five years.