The shelf life of embroidery thread is directly proportionate to the care that you give it. To help your threads have as long a life as possible, keep storage conditions between 50 to 70 degrees F with 40 to 60 percent humidity. Threads will last longer if they are kept covered when not in use to avoid dust, which can dull thread finishes. Keep threads out of direct sunlight to prevent color fading and do your best to avoid dropping any threads. Dropping a cone can create “bruising,” which is a soft spot in the thread that can cause thread breaks while embroidering. At the very least, thread should be stored vertically at room temperature, with the thread out of direct sunlight.