If a duster stays in it's tube and just chills, it's happy. When stressed out, it can either shed it's crown (the feathery part) and regrow it later, or even just abandon it's tube and go hide, growing a new tube as it does so. I lost my pink duster and was sure it was dead. Then weeks later, I see the crown poking up out of the sand behind a rock. It dug down and made a new tube.
Generally, unless stressed out, they do not move.
Someone stop me! Please! But... not just yet...
55 Gal Tropical FW
55 Gal Mixed Reef