Keep them in the container they come in - they will last 2-3 weeks at room temperature. You can store them in a wine fridge for longer (I don't think they survive below 50 degrees) if you have the equipment. My beardie is about the same age, and eats anywhere from 30-50 throughout the day. I only dust them with his multi-vitamin when he needs at, as the worms are packed with calcium. A quick tip - phoenix worms stink of ammonia, and your beardie may not eat them - if this happens, rinse them in a bowl with some warm tap water. The packing material sinks to the bottom, the worms float, and they are super wriggly and enticing to your beardie.