In ESB Luke arrived in Bespin and obviously left his X-Wing, his flight suit, and his helmet behind. Ultimately he ended up on an exterior weather antenna at the bottom of Cloud City with only the clothes he was wearing. I believe most of us assume that his X-Wing was impounded by the Galactic Empire and not used as an escape vehicle by one of Cloud City's citizens (unless Luke left the ignition keys). Yet, after having rescued Han, Chewie and Leia in ROJ we see him in another X-Wing Cockpit - wearing his same old and battered helmet. The unique scratchmarks (like the one at the bottom of the bird logo) and other details (like the handpainted yellow stripes at the front ridge of his helmet) clearly reveal it's still the same helmet, which just has gotten a few more scratches between the time it was left behind in Cloud City and worn again by Luke upon leaving Tatooine. What's this helmet's story we haven't heard, yet?